Understanding the Pregnancy Weight Gain Calculator
Healthy weight gain during pregnancy supports your baby’s growth while protecting your own health. This calculator suggests a recommended range based on your pre-pregnancy BMI and how far along you are, following guidelines from health authorities so you have a realistic target rather than guessing.
Recommendations depend on starting weight
Guidelines from the Institute of Medicine tie recommended gain to pre-pregnancy BMI: people who start at a lower weight are advised to gain more, while those starting heavier are advised to gain less. For a typical single pregnancy at a normal starting BMI, the recommended total is roughly 25–35 pounds, most of it in the second and third trimesters.
Where the weight goes
Pregnancy weight is not just the baby. It includes the placenta, amniotic fluid, increased blood volume, larger breasts and uterus, and some maternal fat stores that support breastfeeding. Understanding this can ease anxiety about the number on the scale — steady, gradual gain within your range is the goal, not a specific weekly figure.
Tips & things to know
- •Recommended gain depends on your pre-pregnancy BMI.
- •Most weight gain happens in the second and third trimesters.
- •Always follow your own provider’s guidance, which accounts for your full health picture.