🤰 Pregnancy Weight Gain Calculator
Gaining the right amount of weight in pregnancy supports the baby's growth while keeping risks low for both mother and child. The Institute of Medicine publishes a recommended total gain range that depends on your body mass index before pregnancy.
Enter your pre-pregnancy height and weight and the calculator places your BMI into one of four bands — underweight, normal weight, overweight or obese — each with its own gain range.
How to use this calculator
Enter your pre-pregnancy height and weight, and the tool shows your BMI band and the recommended total weight gain range.
- Enter your Height in the cm field.
- Enter your pre-pregnancy Weight in the kg field.
- Read the recommended gain range shown in the headline result.
- Check your BMI value and category underneath for context.
Frequently asked questions
Where do these ranges come from?
They come from the Institute of Medicine guidelines, which set a total gain range for each pre-pregnancy BMI band: underweight, normal weight, overweight and obese. Doctors worldwide use these bands as the starting reference.
What is the range for a normal BMI?
For a pre-pregnancy BMI between 18.5 and 24.9 the recommended total gain is 11.5 to 16 kg. A 165 cm woman weighing 60 kg has a BMI of 22, so she lands in this band.
Do twins change the recommendation?
Yes. Twin pregnancies have higher recommended ranges than the single-baby figures this calculator shows, and medical conditions can change the target too. Always confirm your personal range with your doctor.
Is the gain supposed to be steady each month?
No. Very little is gained in the first trimester, then roughly 0.4 to 0.5 kg per week in the second and third for a normal-BMI pregnancy. The calculator gives the total; your doctor tracks the pace.