Pregnancy Weight Gain Calculator

The Pregnancy Weight Gain Calculator estimates a schedule for healthy weight gain based on weight gain guidelines from the Institute of Medicine and height and weight measurements before pregnancy.

Your Current Pregnancy Stage
Pregnant with Twins  
Your Height
feet   inches
Your Weight Before Pregnancy pounds
Your Weight Now pounds
Your Height cm
Your Weight Before Pregnancy kg
Your Weight Now kg

Recommended Weight Gain

While weight gain during pregnancy is normal and necessary, studies have shown that certain ranges of weight gain given a specific body mass index (BMI) result in more positive outcomes for both fetus and mother.1 Weight gain during pregnancy is attributed to the weight of the fetus, as well as a number of other factors, as shown in the table below.


Pregnancy Weight Gain Distribution2

Enlarged breasts1-3 pounds
Enlarged uterus2 pounds
Placenta1.5 pounds
Amniotic fluid2 pounds
Increased blood volume3-4 pounds
Increased fluid volume2-3 pounds
Fat stores6-8 pounds

The weight gain guidelines from the Institute of Medicine are shown in the table below, but note that these are only recommendations and that weight gain between women varies. As such, a health care provider should be consulted to more accurately determine each person's specific needs.


Recommendations for Total Weight Gain During Pregnancy by Prepregnancy BMI1

Prepregnancy
BMI (kg/m2)
Category Total Weight
Gain Range
Total Weight Gain Range
for Pregnancy with Twins
<18.5 Underweight 28-40 lbs  
18.5-24.9 Normal Weight 25-35 lbs 37-54 lbs
25.0-29.9 Overweight 15-25 lbs 31-50 lbs
>30.0 Obese 11-20 lbs 25-42 lbs

Generally, it is recommended that pregnant women gain only 1-4 pounds during the first 3 months of pregnancy, and 1 pound per week during the remainder of the pregnancy. It is possible to achieve this by consuming an additional ~300 calories per day.2

Potential Complications of Suboptimal Weight Gain

There are adverse effects for either insufficient or excessive weight gain during pregnancy. Insufficient weight gain can compromise the health of the fetus and cause preterm, or premature birth; excessive weight gain can cause labor complications, giving birth to significantly larger than average fetuses, postpartum weight retention, as well as increase the risk of requiring a caesarean section.


  1. Institute of Medicine. 2009. "Weight Gain During Pregnancy: Reexamining The Guidelines." http://www.nationalacademies.org/hmd/~/media/Files/Report%20Files/2009/Weight-Gain-During-Pregnancy-Reexamining-the-Guidelines/Report%20Brief%20-%20Weight%20Gain%20During%20Pregnancy.pdf.
  2. Mayo Clinic. 2017. "Pregnancy weight gain: What's healthy?" https://www.mayoclinic.org/healthy-lifestyle/pregnancy-week-by-week/in-depth/pregnancy-weight-gain/art-20044360?pg=1.