Pregnancy weight gain calculator

Pregnancy weight gain calculator: what it is for

How much weight to gain during pregnancy depends on your BMI before pregnancy. The calculator uses the Institute of Medicine (2009) ranges, widely used in prenatal care: 12.5 to 18 kg for underweight, 11.5 to 16 kg for normal weight, 7 to 11.5 kg for overweight and 5 to 9 kg for obesity, with the weekly rate for each range. A chart shows the expected range week by week and where you are.

Everything is calculated in your browser: no health data is sent to or stored on a server.

How to use

1. Enter your height and pre-pregnancy weight.
2. Type your current weight and week of pregnancy.
3. See whether your gain is within, below or above the range.

When to use it

• Tracking weight between prenatal appointments.
• Knowing the total gain goal from the start.
• Bringing the numbers to discuss with your doctor.

Frequently asked questions

How much weight is recommended to gain during pregnancy?

According to the Institute of Medicine guidelines (IOM, 2009), it depends on your BMI before pregnancy: underweight (BMI < 18.5), 12.5 to 18 kg; normal weight (18.5 to 24.9), 11.5 to 16 kg; overweight (25 to 29.9), 7 to 11.5 kg; obesity (30 or more), 5 to 9 kg.

How is the gain spread over the weeks?

In the first trimester the gain is usually small, 0.5 to 2 kg in total. From week 14, the recommended weekly rate is about 0.44 to 0.58 kg for underweight, 0.35 to 0.50 kg for normal weight, 0.23 to 0.33 kg for overweight and 0.17 to 0.27 kg for obesity.

What about twins?

The ranges are larger and different. This calculator is for single pregnancies. In any case, your prenatal care team is the one who sets the right goal for you.

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.

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