Pregnancy Weight Gain Calculator
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weeks
Find your recommended pregnancy weight gain based on pre-pregnancy BMI. Includes trimester-by-trimester guidelines.
Enter your values below and click Calculate for instant results.
Weight gain recommendations during pregnancy are based on pre-pregnancy BMI, as set by the Institute of Medicine and endorsed by major obstetric organizations. The guidelines exist because both insufficient and excessive weight gain during pregnancy carry health risks for both mother and baby.
Pregnancy weight gain does not come entirely from the baby. A typical breakdown for a person gaining 30 lbs during pregnancy includes the baby (7 to 8 lbs), placenta (1 to 1.5 lbs), amniotic fluid (about 2 lbs), uterine growth (about 2 lbs), breast tissue (1 to 3 lbs), blood volume increase (3 to 4 lbs), fluid retention (2 to 3 lbs), and fat and protein stores (6 to 8 lbs).
Most guidelines recommend minimal weight gain in the first trimester (1 to 4.5 lbs total), as the baby is very small and caloric needs barely increase in these early weeks. Most pregnancy weight gain occurs in the second and third trimesters, when the rate increases to roughly 0.5 to 1 lb per week depending on pre-pregnancy BMI.
Gaining less than recommended increases the risk of having a low birth weight baby, which is associated with developmental challenges. Gaining more than recommended increases the risk of gestational diabetes, high blood pressure, need for cesarean delivery, difficulty losing weight postpartum, and higher birth weight in the baby. Both scenarios carry real risks, which is why individualized guidance from a healthcare provider is important throughout pregnancy.
This calculator provides general guidelines based on established medical recommendations. Individual circumstances vary, and your healthcare provider may recommend different targets based on your specific situation. Never attempt to diet or restrict calories during pregnancy without medical supervision.