Pregnancy Weight Gain Calculator
See your recommended total pregnancy weight gain using Institute of Medicine (IOM) guidelines, and how much you should have gained by your current week.
Your details
How to use this calculator
1. Enter your pre-pregnancy weight and height
Use the weight you were at before becoming pregnant. This sets your pre-pregnancy BMI, which is what the IOM ranges are based on.
2. Set your current week and pregnancy type
Type how many weeks along you are and choose singleton or twins. Twin pregnancies have higher recommended ranges.
3. Read the recommendation
The headline shows your recommended total gain for the whole pregnancy. The "by week" card estimates how much of that you'd typically have gained by now.
Why the range is wide
Healthy gain varies from person to person and week to week. Treat the numbers as a guide and look at the overall trend rather than any single weigh-in.
About pregnancy weight gain
How much weight should I gain in pregnancy?
The Institute of Medicine bases the recommended total on your pre-pregnancy BMI: roughly 28-40 lb if underweight, 25-35 lb at a healthy weight, 15-25 lb if overweight and 11-20 lb with obesity for a single baby. Twin pregnancies have higher ranges.
How is the weight gain spread across the pregnancy?
Gain is usually small in the first trimester (about 1 to 4.5 lb) and then steadier through the second and third trimesters. This tool estimates where your cumulative gain should be by your current week.
Not medical advice
These ranges are general guidance, not a personal target. Your doctor or midwife may recommend a different goal based on your health, so always consult a professional.