Pregnancy Weight Gain Calculator
Estimate a healthy weight gain range for your pregnancy based on pre-pregnancy BMI.
These ranges follow the widely used Institute of Medicine (IOM) guidelines, which set target weight gain based on pre-pregnancy BMI. Underweight and normal-weight women are generally advised to gain more than overweight or obese women, since the total is meant to support fetal growth without adding unnecessary strain.
How the ranges work
Most of the gain happens in the second and third trimesters, roughly 1 to 2 pounds per week for a normal-BMI singleton pregnancy after the first trimester, with less in the first trimester (2 to 4 pounds total). Twin pregnancies carry a higher target range.
This tool gives a general reference range, not medical advice. Weight gain needs vary by individual health history, and your provider's guidance for your specific pregnancy always takes priority over a generic calculator.