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Salário, rescisão, financiamento, juros, porcentagem e outras contas do dia a dia.

Work and salary 18Finance and investing 34Business and freelancers 12Construction and home 21Electricity and energy 16Farming 5Car and travel 10Cooking and parties 9Math 26Physics and chemistry 17School and college 2Maps and coordinates 3Converters 10Everyday 15

Work and salary 18

Retirement calculatorFind out how much you need to save and invest each month to retire with the income you want, living only off the returns.Open →
Class absence calculator (how many can I miss?)Find out how many more classes you can miss without failing for attendance, from the course hours and a minimum attendance of 75%.Open →
Convert hours to decimalConvert hours and minutes to decimal hours (8:30 = 8.5) and back, with a minutes table and pay calculation by the hour.Open →
Vehicle cost per mile calculatorWork out the cost per mile to reimburse someone who uses their own car or motorcycle for work: fuel plus wear and tear, maintenance and depreciation.Open →
Add up employment periodsAdd up several periods of work (jobs, freelancing, internships) and see the total time in years, months and days, without counting overlapping periods twice.Open →
1099 vs W-2 calculator (contractor vs employee pay)Compare a W-2 salary with a 1099 contractor rate: self-employment tax vs FICA, the value of employer benefits like health insurance, 401(k) match and paid time off, and the hourly rate a 1099 job must pay to match the W-2 offer.Open →
Bonus tax calculatorSee how much of your bonus you keep after federal withholding (22% supplemental rate), Social Security, Medicare and state tax.Open →
FICA tax calculator (Social Security and Medicare)Calculate the Social Security and Medicare (FICA) taxes taken from your paycheck, including the wage base cap and the additional Medicare tax.Open →
Mileage reimbursement calculator (IRS rate 2026)Calculate mileage reimbursement or the mileage deduction with the IRS standard mileage rates for 2026: business, medical and moving, and charitable miles, including the midyear change on July 1, 2026. Add trips and round trips and get the total.Open →
Overtime calculatorCalculate overtime pay at time and a half or double time, and your total pay for the week.Open →
Paycheck calculatorEstimate your take-home pay per paycheck after federal income tax, Social Security, Medicare, state tax and 401(k), with 2026 tax brackets.Open →
PTO accrual calculatorCalculate how much paid time off you earn per paycheck or per hour worked, your balance by a date and when you hit the accrual cap.Open →
Quarterly estimated tax calculator (Form 1040-ES)Figure out how much to pay in quarterly estimated taxes for 2026 or 2027 with the IRS safe harbor rules: 90% of this year's tax or 100% of last year's (110% if your AGI was over $150,000), minus withholding. See each payment and its due date.Open →
Salary to hourly calculatorConvert a yearly salary to an hourly wage, or an hourly wage to a yearly, monthly and weekly salary.Open →
Social Security benefits calculatorEstimate your monthly Social Security retirement benefit from your average earnings, and compare claiming at 62, full retirement age or 70.Open →
State income tax calculatorEstimate your state income tax in any of the 50 states and DC: no-tax states, flat-tax states and progressive states, with your effective rate.Open →
Tax refund estimatorEstimate your federal tax refund or how much you will owe, from your wages, withholding, filing status and children.Open →
W-4 withholding calculatorCheck whether your paycheck withholding will cover your federal tax and how much extra to withhold per paycheck on your W-4 (Step 4c).Open →

Finance and investing 34

Extra payment loan calculatorSee how much interest you save by making an extra payment on your loan, shortening the term or lowering the payment, with fixed payments or constant amortization.Open →
Discount calculatorFinal price after a discount and how much you save.Open →
Inflation calculatorSee how much something will cost in the future with inflation and how much purchasing power you lose over the years.Open →
First million calculatorHow long until you reach your first million.Open →
Find the interest rate of an installment purchaseFind the interest hidden in installment plans: enter the cash price, the number of installments and the amount of each.Open →
Compound interestSee how much your money grows with monthly contributions.Open →
Simple interest calculatorCalculate simple interest, final amount, rate or time, with the I = P × r × t formula explained.Open →
Late fee and interest calculatorCalculate how much to pay on an overdue bill, rent or invoice: a late fee plus daily interest prorated by the days late.Open →
Price per square foot and square meterCalculate the price per square foot or square meter of houses, apartments and land and compare several properties side by side: price, area, price per unit of area and HOA fee per unit, to see which is cheapest.Open →
Stock average cost calculatorWork out the average cost of your stocks, ETFs, funds or crypto from your buys and sells, including fees, the realized gain or loss on each sale and the result at market price.Open →
Portfolio rebalancing calculatorEnter how much you have in each asset class and the target percentage, and see how much to buy or sell of each one to get back to your target allocation, or how to split a new contribution without selling anything.Open →
50/30/20 budget ruleSplit your income with the 50/30/20 rule: how much goes to needs, wants and savings or paying off debt.Open →
Rule of 72 (time to double your money)Find out how long an investment takes to double, triple or grow tenfold at a given interest rate, with the rule of 72 and the exact calculation, or what rate you need to double it in a given time.Open →
Real rate of return calculator (after inflation)Find out how much your investment really earned after inflation, using the Fisher equation, and how much it needs to earn to beat inflation plus the real return you want.Open →
Loan amortization calculatorPayments with fixed installments or constant principal.Open →
Equivalent interest rate calculatorConvert compound interest rates between day, month, quarter, half year and year: find out what 1% a month is per year and vice versa.Open →
401(k) calculatorSee how much your 401(k) can grow by retirement with your contributions, your employer match, salary raises and the 2026 contribution limit.Open →
APR to APY calculatorConvert APR to APY and APY to APR with daily, monthly, quarterly or yearly compounding, and see the interest earned on a deposit.Open →
Capital gains tax calculatorEstimate the federal tax on selling stocks, crypto or property: short-term vs long-term rates (0%, 15%, 20%) and the 3.8% net investment income tax.Open →
Closing costs calculatorEstimate the buyer's closing costs on a home purchase: lender fees, appraisal, title insurance, transfer taxes and prepaid taxes and insurance, plus cash to close.Open →
Credit card payoff calculatorSee how long it takes to pay off a credit card and how much interest you will pay, or what monthly payment clears it by a target date.Open →
Debt snowball vs avalanche calculatorList your debts and see how long it takes to pay them all off with the debt snowball (smallest balance first) and the debt avalanche (highest interest first), how much interest each method costs, and the payoff order month by month.Open →
Debt-to-income (DTI) ratio calculatorCalculate your front-end and back-end debt-to-income ratio, the numbers lenders use to approve a mortgage, car loan or personal loan.Open →
Federal income tax calculatorEstimate your 2026 federal income tax with the new brackets and standard deduction, and see your marginal and effective tax rate.Open →
HELOC and home equity calculatorFind out how much you can borrow against your home with a HELOC or home equity loan from the home value, mortgage balance and the lender's maximum combined loan-to-value (CLTV), and estimate the interest-only and repayment payments.Open →
Home affordability calculatorFind out how much house you can afford from your income, debts, down payment and mortgage rate, using the 28/36 rule lenders follow.Open →
Mortgage calculatorEstimate your monthly mortgage payment with principal, interest, property tax, homeowners insurance, PMI and HOA, plus the total interest over the loan.Open →
Property tax calculatorEstimate your yearly and monthly property tax from your home value and your state's average effective rate, with exemptions like the homestead exemption.Open →
Refinance break-even calculatorFind out if refinancing your mortgage pays off: compare your current payment with the new one, see the monthly savings, how many months it takes for the savings to cover the closing costs, and the total interest of both loans.Open →
Rent affordability calculator (how much rent can I afford?)Find out how much rent you can afford from your income with the 30% rule, the 40x rent rule landlords use, and a budget based on your take-home pay and monthly debts.Open →
Rent vs buy calculatorCompare renting and buying a home over the years you plan to stay: mortgage, property tax, upkeep, appreciation, selling costs and investing the difference.Open →
RMD calculator (required minimum distribution)Calculate your required minimum distribution (RMD) from an IRA, 401(k) or 403(b) with the IRS Uniform Lifetime Table, find the age your RMDs start under SECURE 2.0 (73 or 75) and project the next years.Open →
Roth IRA calculatorProject your Roth IRA balance at retirement with yearly contributions and growth, and check how much you can contribute in 2026 based on your income.Open →
Student loan calculatorCalculate your monthly student loan payment, total interest and how much time and money extra payments save.Open →

Business and freelancers 12

Freight cost per mile/km calculatorCalculate the cost and price of a trucking load: distance, truck fuel economy, diesel price, tolls, wear per km, per diem and profit margin, with the rate per kilometer.Open →
ROI calculatorCalculate the return on investment (ROI) of campaigns, equipment or projects, with annualized ROI and payback period.Open →
Website conversion rate calculatorCalculate the conversion rate of your website or online store (sales, orders or leads divided by visits), the revenue, the revenue per visit and how much you would earn if conversion went up. It also works out how many visits you need to hit a sales goal.Open →
Operating cycle, cash conversion cycle and working capitalCalculate days inventory outstanding, days sales outstanding and days payable outstanding, the operating cycle, the cash conversion cycle and your company's working capital needs.Open →
Online cash flow trackerSimple cash flow tracking for freelancers and small businesses: record money in and out, see the month's balance by category and export to CSV.Open →
Weighted decision matrixCompare options with criteria and weights to make tough decisions: score each alternative, adjust how much each criterion matters and see the final score and ranking.Open →
Break-even point calculatorCalculate how many units to sell and how much revenue you need each month to cover all your costs, with contribution margin and margin of safety.Open →
Reorder point and safety stock calculatorKnow when to place your next order with the supplier: reorder point, safety stock, days of coverage and economic order quantity.Open →
Selling price calculatorFind out what price to sell at with profit, taxes and fees.Open →
Website pricing calculator (for freelancers)Work out how much to charge for a website, landing page or online store: hours for each stage, your hourly rate, the costs of domain, hosting, plugins and themes, taxes and a buffer for surprises. See the project price, the deposit, the installments and a monthly maintenance fee.Open →
Sales tax calculatorAdd sales tax to a price or take it out of a total. Works with any state, county or city rate.Open →
Self-employment tax calculatorCalculate the 15.3% self-employment tax (Social Security and Medicare) for freelancers, 1099 contractors and small business owners, with the 2026 wage base.Open →

Construction and home 21

Water tank size calculatorCalculate the right water tank size for your home from the number of residents, use per person and days of reserve.Open →
Wire fence calculatorCalculate how many posts and how many meters and rolls of plain or barbed wire to buy to fence a lot, pasture or farm.Open →
Concrete calculatorCalculate the volume of concrete for a slab, footing, beam or subfloor and how many bags of cement, sand and gravel to buy for the mix ratio.Open →
Sod calculatorCalculate how many m² and how many pieces or rolls of sod to buy for your yard, with cutting waste, and the soil to prepare the ground.Open →
Wallpaper calculatorCalculate how many rolls of wallpaper to buy from the width and height of your walls, minus doors and windows, taking the pattern repeat into account.Open →
Tile and flooring calculatorCalculate how many tiles and boxes of flooring, porcelain or wall tile to buy, with waste, thinset and grout.Open →
Wall plaster and mortar calculatorCalculate the mortar for scratch coat, base coat and finish coat on walls: volume per layer, bags of cement, sand and lime from the mix, or bags of premixed mortar, with waste included.Open →
Roof tile calculatorCalculate how many roof tiles to buy (clay, concrete or fiber cement) from the area, the roof pitch and the waste.Open →
Brick and block calculatorCalculate how many bricks, concrete blocks or clay blocks to buy for a wall, minus doors and windows, with waste and mortar.Open →
Paint calculatorCalculate how many liters and cans of paint to buy to paint walls and ceiling, minus doors and windows.Open →
Roof pitch calculatorConvert roof pitch between percentage, degrees and x:12 ratio, calculate the ridge height from the span and the true roof area with the pitch factor.Open →
Simple online floor plan makerDraw a simple floor plan to scale: place the rooms (living room, bedrooms, kitchen, bathroom, laundry, balcony, garage), drag them, set the sizes in meters and see the area of each room and the total area. Download as PNG or SVG.Open →
Potting soil calculatorCalculate how many quarts of potting soil fit in a round or square pot or a planter box, and how many bags to buy to fill several pots, subtracting the drainage layer.Open →
Board foot calculatorCalculate board feet of lumber from thickness, width and length, for one board or many, and the total price.Open →
Deck calculator (boards, joists and screws)Estimate the materials for a deck: decking boards in 8, 12 or 16 ft lengths, joists at 12 or 16 inches on center, deck screws or hidden fasteners, and the cost, from the deck size and board width.Open →
Drywall calculatorEstimate how many drywall sheets you need for a room's walls and ceiling, minus doors and windows, plus joint compound, tape and screws. Choose 4×8, 4×10 or 4×12 sheets.Open →
Feet and inches calculatorAdd and subtract lengths in feet, inches and fractions (like 5' 7 3/8"), multiply or divide them, and convert to inches, centimeters and meters.Open →
Mulch calculatorCalculate how much mulch, soil or gravel you need in cubic yards and bags from the bed area and depth in feet and inches.Open →
Roofing calculator (squares and shingle bundles)Calculate the roof area from the house footprint and roof pitch, convert it to roofing squares and estimate the bundles of shingles, underlayment rolls and cost, with an extra percentage for waste.Open →
Square footage calculatorCalculate the square footage of a room, a house or any area: rectangles, L-shapes, triangles and circles, in feet and inches. Add several areas together and get the cost from a price per square foot.Open →
Stair calculatorCalculate the number of steps, riser height, tread depth, total run and stringer length for a staircase from the total rise, and check them against the common residential code limits (7 3/4 in max riser, 10 in min tread).Open →

Electricity and energy 16

Resistors in series and parallel calculatorCalculate the equivalent resistance of resistors in series or parallel, and of capacitors too, by typing the values separated by commas or lines.Open →
555 timer calculatorCalculate the frequency, period, high and low time and duty cycle of the 555 timer in astable mode, the pulse width in monostable mode, and find R1 and R2 for the frequency you want.Open →
Wire size and breaker calculator (mm²)Calculate the wire size (mm²) and breaker from the power, voltage and length of the circuit, considering current capacity and voltage drop under IEC-based rules (Brazilian NBR 5410).Open →
BTU calculator (air conditioner)Find out how many BTUs your air conditioner needs for your room, from the area, number of people, appliances and afternoon sun.Open →
Solar panel calculatorEstimate how many solar panels you need, the system size in kWp and the roof area from your electric bill usage.Open →
Lighting calculator (lumens per room)Calculate how many lumens each room needs from the type of room and its area, and how many LED bulbs to buy, with the total wattage and estimated monthly use.Open →
Capacitor code: 104, 103, 473 and moreFind the value of a ceramic or film capacitor from its printed code, such as 104, 103J, 473K or 2A104J, in pF, nF and µF, with tolerance and voltage, or get the code from the value.Open →
Resistor color codeFind a resistor's value from its color bands (4, 5 or 6 bands), with tolerance and temperature coefficient, or find the colors from the value in ohms.Open →
RC time constant calculatorCalculate the time constant τ = R × C of an RC circuit, the capacitor voltage during charge and discharge at any moment, the time to reach a voltage and the filter cutoff frequency, with a chart of the curve.Open →
Electricity usage calculatorFind out how much electricity each appliance uses per month in kWh and in dollars.Open →
Voltage divider calculatorCalculate the output voltage of a two-resistor divider, with or without a load, the current and power in each resistor, and find the closest pair of standard resistors (E24 series) for the voltage you need.Open →
Electric shower cost calculatorCalculate how much an electric shower costs in electricity and water per month: power, shower length, showers per day and rate. See how much you save with shorter showers or summer mode.Open →
Ohm's Law calculatorEnter two values among voltage, current, resistance and power and calculate the other two with Ohm's Law (V = R × I) and the power formula (P = V × I).Open →
Power bank charge calculatorFind out how many times a power bank charges your phone, earbuds or tablet, taking into account the 3.7 V cell voltage and conversion losses, and how long each charge takes.Open →
Voltage drop calculatorWork out the voltage drop in an electrical circuit from the cable length, wire size, current or power, in single-phase or three-phase circuits, with AWG or mm² wire sizes, compare it with the usual 3% and 5% limits and see the smallest wire size that meets them.Open →
LED resistor calculatorWork out the right resistor for one or more LEDs in series: enter the supply voltage and the LED voltage and current, and see the resistance, the standard value and the power rating.Open →

Farming 5

Rainfall in litersConvert millimeters of rain into liters and calculate how much rainwater your roof can collect (area × rainfall × runoff coefficient), in liters, m³ and water tanks.Open →
Cattle weight gain calculator (ADG)Calculate cattle average daily gain (ADG) between two weighings, the arrobas (15 kg of carcass) produced in the period and how many days are left until the animal reaches slaughter weight.Open →
Dog, cat and other animal pregnancy calculatorCalculate the likely due date of a dog, cat, rabbit, pig, sheep, goat, cow or mare from the mating date, with the birth window and which day of pregnancy she's on.Open →
Plant spacing calculator (plants per area)Calculate how many seedlings, plants or seeds fit in a plot, bed or hectare from the row spacing and plant spacing, in square, rectangular or triangular (quincunx) planting.Open →
Pasture stocking rate calculatorCalculate your pasture's stocking rate in animal units per acre (AU/acre): enter your groups of animals with their average weight and the area, and see the AUs, the live weight per acre and how many head fit your target stocking rate.Open →

Car and travel 10

Fuel tank range calculatorFind out how far your car can go on a full tank or on the fuel left, how many fuel stops a trip needs and how much it costs to fill up.Open →
Will my bag fit as a carry-on?Enter your bag's size and weight and see if it fits as a personal item, carry-on or checked bag under the limits most airlines use.Open →
Tire size calculator (compare sizes and rims)Compare two tire sizes, like 185/65 R15 and 195/55 R16: diameter, sidewall height, circumference, revolutions per km and the speedometer error when you change rims or tires.Open →
EV charging time and cost calculatorCalculate how long it takes and how much it costs to charge an electric car: battery size, current and target percentage, charger power (outlet, wallbox or fast charger) and rate. See the miles/km added too.Open →
Trip cost calculatorHow much you will spend on fuel and tolls.Open →
Ethanol or gasoline (flex fuel)Find out which fuel is the better deal for a flex-fuel car.Open →
Travel budget calculatorPlan how much money to take on your trip: flights, lodging, food, transportation, tours, insurance and shopping, per person and per day, with currency conversion.Open →
Auto loan calculatorCalculate your monthly car payment with price, down payment, trade-in, sales tax, fees, APR and loan term, plus total interest.Open →
Car lease calculatorCalculate your monthly car lease payment from the MSRP, negotiated price, down payment, residual value, money factor or APR, term and sales tax, and compare the total cost of leasing with buying on a loan.Open →
Gas cost trip calculatorCalculate how much gas a road trip will cost from the distance in miles, your car's MPG and the price per gallon. Round trip, split the cost among passengers and see the gallons and fill-ups you need.Open →

Cooking and parties 9

Recipe scaler (double or halve servings)Paste the ingredient list and change the yield: the tool multiplies the amounts to double, triple or halve the recipe, including fractions like 1/2 cup.Open →
BBQ calculatorHow much meat and drinks to buy per guest.Open →
Party food calculatorCalculate how many snacks, sweets, cake, soda, beer and ice to buy for your party.Open →
Pizza dough calculatorCalculate the flour, water, salt, yeast and olive oil for pizza dough from the number of pizzas, the weight of each ball and the hydration you want.Open →
Yeast converterConvert fresh, active dry and instant yeast: find out how many grams of dry yeast replace the fresh yeast in a recipe and vice versa.Open →
Cooking measurement converterConvert cups, tablespoons and teaspoons into grams and milliliters for flour, sugar, butter, milk, rice and other ingredients.Open →
Cake pan size converterSwitch the pan in your recipe: compare the area of round, square and rectangular pans and find out how much to multiply the ingredients for a cake, pie or flan.Open →
Baker's percentage calculatorCalculate the baker's percentage of each ingredient relative to the flour and the dough hydration, and scale your bread recipe to a different amount of flour or total weight.Open →
Coffee to water ratio calculatorHow much ground coffee to use for each cup: the coffee to water ratio for drip, French press, moka pot, espresso and cold brew.Open →

Math 26

Permutation and combination calculatorCalculate factorial, permutations and combinations, with and without repetition, showing the formula.Open →
Scientific calculatorOnline scientific calculator with sine, cosine, tangent, log, root, power, factorial and history.Open →
Scale calculatorConvert real measurements to the scale of a drawing, floor plan, map or model (1:50, 1:100, 1:25,000) and back. Also find the scale from a real measurement and the one on paper.Open →
Z-score and normal distribution calculatorCalculate the z-score of a value, the cumulative probability and the percentile on the normal distribution, or go the other way, with a bell curve chart and the shaded area.Open →
Statistics calculator (standard deviation)Paste a list of numbers and see the mean, median, mode, standard deviation, variance, quartiles, range and coefficient of variation.Open →
Fraction calculatorAdd, subtract, multiply and divide fractions.Open →
Logarithm calculatorCalculate logarithms in any base, natural log (ln) and common log, find the base or the argument, and solve simple exponential equations like 2ˣ = 32.Open →
Matrix calculatorCalculate the determinant, inverse, transpose, sum, difference and product of matrices up to 6×6, with fractions when the result isn't a whole number.Open →
Percentage calculatorWhat is X% of Y, increases, discounts and percent change.Open →
Sample size calculatorCalculate how many people to survey from the confidence level, margin of error and population size, or find the margin of error of a sample you already have.Open →
Angle converterConvert angles between degrees, radians, gradians, turns and degrees, minutes and seconds (DMS), with the sine, cosine and tangent of the angle and the equivalent angle between 0° and 360°.Open →
Quadratic equation solverSolve quadratic equations with the quadratic formula, step by step, and see the graph.Open →
Online graphing calculator (plot functions)Plot math functions: lines, parabolas, polynomials, exponentials, logarithms and trig functions, up to 4 functions together. Adjust the x and y range, read the points by hovering and download as PNG or SVG.Open →
Confidence interval calculatorCalculate the confidence interval for a mean (with Student's t or the normal distribution) or a proportion, from summary data or a pasted list of numbers.Open →
Average calculatorMean, weighted average, median and mode.Open →
LCM and GCD calculatorCalculate the least common multiple and greatest common divisor of several numbers, with the prime factorization.Open →
Number to wordsWrite numbers and dollar amounts in words.Open →
Prime numbers and factorizationFind out if a number is prime, factor it into primes, see all its divisors and list the primes up to any limit.Open →
Roman numeral converterConvert numbers to Roman numerals and back.Open →
Arithmetic and geometric sequence calculatorFind the general term, the nth term and the sum of the terms of arithmetic and geometric sequences, with the list of terms and the sum of an infinite geometric series.Open →
Rule of three calculatorSolve direct and inverse proportions.Open →
Compound rule of threeSolve compound rule of three problems with up to 4 quantities, directly or inversely proportional, with the math step by step.Open →
Linear regression and correlation calculatorPaste X and Y value pairs and get the regression line (y = a + bx), Pearson's correlation coefficient, R², predictions and a scatter plot with the trend line.Open →
System of equations calculatorSolve linear systems of 2 or 3 equations with 2 or 3 unknowns, with determinants (Cramer's rule) and the classification of the system.Open →
Online multiplication tableMultiplication, division, addition and subtraction tables from 1 to 10 (or any number), printable and with a practice game for kids.Open →
Pythagorean theorem and right triangle calculatorCalculate the hypotenuse or a leg with the Pythagorean theorem and see the angles, area, perimeter and height of the right triangle, with a drawing and step-by-step work.Open →

Physics and chemistry 17

Chemical equation balancerType a chemical equation, like C3H8 + O2 = CO2 + H2O, and get the smallest whole-number coefficients that balance the reaction, with an atom count check for each element.Open →
Dilution calculator (C1V1 = C2V2)Calculate solution dilutions with C1·V1 = C2·V2: enter three values to find the fourth, plus how much solvent to add. Works for mol/L, g/L, percent and ppm.Open →
Molarity calculator (mol/L)Calculate the molarity of a solution, the mass of solute to prepare a volume or the volume needed. Type the chemical formula and the molar mass is calculated for you.Open →
pH and pOH calculatorCalculate pH, pOH, [H⁺] and [OH⁻] from any one of them or from the concentration of a strong acid or base, and see whether the solution is acidic, neutral or basic at 25 °C.Open →
Kinematics calculator (constant acceleration)Solve constant acceleration problems: enter three of initial velocity, final velocity, acceleration, time and displacement and calculate the others with the equations of motion and Torricelli's equation.Open →
Braking distance calculatorCalculate a car's stopping distance: the part covered during the reaction time and the braking part, on dry, wet, dirt or icy roads, with a table for several speeds.Open →
Electron configuration (Aufbau diagram)Write the electron configuration of any element or ion with the Aufbau (Madelung) diagram: energy order, noble gas shorthand, K to Q shells and valence shell.Open →
Kinetic and potential energy calculatorCalculate the kinetic energy (½mv²), gravitational potential energy (mgh) and mechanical energy of a body, and see its speed when falling and the height it reaches when going up.Open →
Age on other planetsFind out how old you'd be on Mercury, Venus, Mars, Jupiter, Saturn, Uranus, Neptune and Pluto and when your next birthday on each planet will be.Open →
Projectile motion simulatorCalculate range, maximum height and time of flight of an oblique or horizontal launch from the speed, angle and initial height, with a drawing of the trajectory.Open →
Ideal gas law calculatorSolve the ideal gas equation (PV = nRT) and the combined gas law (P1V1/T1 = P2V2/T2): enter the known values in atm, kPa, mmHg, liters and °C and find what's missing.Open →
Molar mass calculatorType a chemical formula, like H2SO4, Ca(OH)2 or CuSO4·5H2O, and see the molar mass in g/mol, the percent composition of each element and the mass of any number of moles.Open →
Weight on other planetsFind out how much you'd weigh on the Moon, Mars, Jupiter and the other planets of the Solar System, with each one's gravity and how high you could jump.Open →
Inclined plane calculatorCalculate the forces on an inclined plane: weight, parallel and normal components, friction, the block's acceleration and the force to push it up the ramp, with or without friction.Open →
Punnett square calculator (genetic cross)Build the Punnett square for a monohybrid, dihybrid or trihybrid cross, such as Aa × Aa or AaBb × AaBb, and see the genotype and phenotype ratios of the offspring.Open →
Free fall calculatorWork out the fall time, impact speed and height in free fall, on Earth, the Moon or Mars, with a table of position and speed at each moment.Open →
Interactive periodic tableThe complete periodic table with all 118 elements: click to see the atomic number, atomic mass, family, period and group, and search by name or symbol.Open →

School and college 2

GPA calculator (weighted average)Calculate your college GPA, the weighted average of your grades by the credits or hours of each course.Open →
Final grade calculator (what do I need?)Find out the grade you need on your last test to pass, with a simple or weighted average.Open →

Maps and coordinates 3

UTM coordinate converterConvert geographic coordinates (latitude and longitude) to UTM and from UTM back to latitude and longitude, with zone, hemisphere, easting and northing, on the GRS 80 / WGS 84 ellipsoid, and see them in degrees, minutes and seconds too.Open →
Distance to the horizonCalculate how far you can see from a given height, such as from a beach, a building, a hill or a plane, with and without atmospheric refraction, the maximum distance to see a tall object and how much of it is hidden by the curvature of the Earth.Open →
Distance between coordinatesCalculate the straight-line distance between two points from their latitude and longitude, in kilometers, miles and nautical miles, with the bearing from one point to the other and the midpoint, using the haversine formula.Open →

Converters 10

Fuel economy converter (mpg, L/100 km and km/L)Convert fuel economy between miles per US gallon (mpg US), imperial gallon (mpg UK), km/L and liters per 100 km, handy for comparing cars and tests from other countries.Open →
Energy converter (J, cal, kWh, BTU)Convert energy units: joule, kilojoule, calorie, kilocalorie, watt-hour, kilowatt-hour, BTU, electronvolt and erg, with every conversion at once.Open →
Unit converterConvert length, weight, volume, area and temperature.Open →
Pressure converter (psi, bar, atm, kPa)Convert pressure units: pascal, kilopascal, bar, psi, atmosphere, mmHg, kgf/cm², meter of water column and inch of mercury, all at once.Open →
Clothing size converterConvert clothing sizes between Brazil, the US, Europe and the UK, for women and men: Brazilian PP, P, M, G and GG, sizes 36 to 50, and XS to XXL.Open →
Temperature converter (Celsius, Fahrenheit, Kelvin)Convert temperatures between Fahrenheit, Celsius, Kelvin and Rankine instantly, with the formula and a reference table.Open →
Speed converter (km/h, m/s, mph, knots)Convert speeds between km/h, m/s, miles per hour, knots, feet per second and Mach, with all units at once.Open →
Inches to millimeters (fractions)Convert inches to millimeters and millimeters to inches, including fractions like 1/4", 3/8", 1/2" and 1 1/4", with a chart of sizes for wrenches, drill bits, pipes and bolts.Open →
Shoe size converter (US, UK, Europe)Convert shoe and sneaker sizes between the United States (men's and women's), the UK, Europe, Brazil and centimeters.Open →
Paper sizes (Letter, Legal, A4, A3)Chart of paper sizes in the A, B and C series (A4, A3, A5, B5, C4...) and the Letter, Legal and Tabloid formats, in millimeters, centimeters, inches and pixels at the resolution you choose.Open →

Everyday 15

Group expense splitter (who owes whom)Split trip, house or barbecue expenses among friends: enter how much each person paid and see who owes whom with the fewest transfers.Open →
Wedding anniversary names by yearFind out which anniversary a couple celebrates from the wedding date, how long they've been together and when the next one is, with the full list from paper to diamond.Open →
Diaper calculatorHow many diapers a baby uses in each size in the first year and how many packs to ask for at the baby shower, split by the number of guests.Open →
Tip calculatorCalculate the tip, the bill total and how much each person pays, with rounding to make paying easier. Works for travel tipping too (15% to 20% in the US).Open →
Day of the week calculatorFind out which day of the week any date fell or will fall on, such as the day you were born, and see which weekday your birthday will be in the coming years.Open →
How many days old am ISee how many days, weeks, hours, minutes and seconds you have lived, with a live counter, and the dates of milestones like 10,000 and 20,000 days old.Open →
Split the billSplit the bar or restaurant bill among friends, with the tip, cover charge and a smaller share for those who did not drink.Open →
Week number of the yearSee which week of the year it is today or on any date, using the ISO 8601 standard, with the day of the year, the days left and a list of every week with its start and end dates.Open →
Unit price calculator (price per pound, ounce or liter)Compare different package sizes at the store and find out which is cheaper by the price per pound, ounce, kilo, liter, meter or unit, and how much you save by picking the best one.Open →
Video storage calculatorWork out how many minutes or hours of video fit on your phone, memory card, flash drive or hard drive, by recording resolution and format (1080p, 4K, HEVC or H.264) or by bitrate.Open →
Online wheel of lifeMake your wheel of life: rate health, career, finances, relationships and other areas from 0 to 10, see the radar chart and download the image to track your progress.Open →
Download time calculatorHow long it takes to download or upload a file, game or movie on your internet connection: enter the size in GB or MB and the speed in Mbps.Open →
When does daylight saving time start and end?See when daylight saving time starts and ends in the United States this year and in the next years, how many days are left until the next clock change, and which states and territories don't change their clocks.Open →
Federal holidays calendar (2026, 2027 and any year)See the 11 U.S. federal holidays for any year with the day of the week, the observed date when the holiday falls on a weekend, and how many days are left until each one. Download the list as a calendar file.Open →
Military time converterConvert military time (24-hour clock) to standard AM/PM time and back, see how to say it out loud, and check the full military time chart from 0000 to 2359.Open →

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