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.
How many bulbs per room
Estimate for general lighting. Commercial projects should follow ISO/CIE 8995-1 and a lighting design.
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Lighting calculator (lumens per room): what it is for
Choose the type of room or enter the lux level you want, type the room dimensions and the type of finish. The calculator estimates the light needed in lumens, how many bulbs to buy from the lumens on the box, the resulting illuminance, the total wattage and the monthly use and cost.
The calculations run in your browser. For commercial projects, follow ISO/CIE 8995-1.
How to use
- Choose the room.
- Enter the dimensions and the bulb.
- See how many bulbs and the energy use.
When to use it
- Plan lighting for a renovation.
- Swap old bulbs for LED.
- Size the lighting of a home office.
Frequently asked questions
How many lux does each room need?
Common reference values for homes: living room and bedroom 100 to 200 lux, kitchen and laundry about 300 lux, bathroom about 200 lux and office or study desk 500 lux. For offices and shops, the ISO/CIE 8995-1 standard sets minimum levels.
How do lux become lumens?
Lux is lumens per square meter. Multiplying the lux level you want by the area gives the light that needs to reach the surface. Since some light is lost on dark walls, high ceilings and closed fixtures, the calculator applies a utilization factor.
How many lumens does an LED bulb have?
Check the box. As a reference, a 9 W LED bulb usually gives about 800 lm, equal to a 60 W incandescent, and a 12 W one is close to 1,100 lm.
Is it really free?
Yes, 100% free. No sign-up, no subscription and no usage limits. All Tools123 tools are free and run right in your browser.