Pregnancy Weight Gain Calculator

Calculate the recommended weight gain during pregnancy based on your pre-pregnancy BMI and current week of pregnancy.

Your weight before becoming pregnant.

Feet portion of your height.

Inches portion of your height.

Your current week of pregnancy (1-42).

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Recommended Weight Gain During Pregnancy

The Institute of Medicine guidelines recommend weight gain based on pre-pregnancy BMI: underweight (BMI < 18.5) should gain 28-40 lbs, normal weight (18.5-24.9) should gain 25-35 lbs, overweight (25-29.9) should gain 15-25 lbs, and obese (BMI 30+) should gain 11-20 lbs. These ranges support healthy fetal development.

Weight Gain by Trimester

Most weight gain occurs in the second and third trimesters. During the first trimester, only 1-5 pounds is typical. In the second and third trimesters, normal-weight women should gain about 1 pound per week. The rate varies by pre-pregnancy BMI — overweight women should gain about 0.6 lbs/week and underweight women about 1.3 lbs/week.

Where Does the Weight Go?

At full term, pregnancy weight gain is distributed approximately as follows: baby (7-8 lbs), placenta (1.5 lbs), amniotic fluid (2 lbs), uterus growth (2 lbs), breast tissue (2 lbs), increased blood volume (4 lbs), body fluids (4 lbs), and maternal fat stores (5-9 lbs). Most of this weight is lost within 6 weeks postpartum.

Managing Weight During Pregnancy

Focus on nutrient-dense foods rather than "eating for two" — you only need about 340 extra calories per day in the second trimester and 450 in the third. Regular moderate exercise (walking, swimming, prenatal yoga) is safe and beneficial for most pregnancies. Never attempt to lose weight during pregnancy without medical guidance.

Frequently Asked Questions