Free Tool
Pregnancy Weight Gain Calculator
A free pregnancy weight gain calculator and tracker. Enter your height and pre-pregnancy weight to see your recommended range, then track where you are this week with a personalized chart.
Your Measurements
Disclaimer: These recommendations are based on the IOM (Institute of Medicine) guidelines for singleton pregnancies. Every pregnancy is different. Your provider may recommend a different weight gain target based on your medical history, activity level, or whether you are carrying multiples. This tool is for informational purposes only.
How Much Weight Should You Gain?
The Institute of Medicine (IOM) sets recommended ranges based on your pre-pregnancy BMI. These numbers account for baby, placenta, amniotic fluid, increased blood volume, breast tissue growth, and the fat stores your body needs for delivery and breastfeeding.
Most weight gain happens after the first trimester. During weeks 1 to 13, many people gain only 1 to 5 pounds (and some lose weight due to nausea). From weeks 14 onward, gaining about half a pound to one pound per week is typical.
These are guidelines, not rules. Some variation is completely normal. Your provider may recommend a different target based on your health history, whether you are carrying multiples, or other factors. What matters most is consistent, gradual gain rather than hitting an exact number.
Where the Weight Goes
Baby and support
- Baby: 7 to 8 lbs
- Placenta: 1 to 2 lbs
- Amniotic fluid: 2 lbs
- Uterus: 2 lbs
Your body
- Blood volume: 3 to 4 lbs
- Breast tissue: 1 to 3 lbs
- Fat stores: 6 to 8 lbs
- Extra fluid: 2 to 3 lbs
Pregnancy Weight Gain Questions
How much weight should I gain during pregnancy?
The recommended range depends on your pre-pregnancy BMI. In the lower BMI range (under 18.5), the IOM suggests 28 to 40 pounds. In the middle range (18.5 to 24.9), 25 to 35 pounds. In the higher range (25 to 29.9), 15 to 25 pounds. At a BMI of 30 or above, 11 to 20 pounds. These are guidelines for singleton pregnancies, and your provider may tailor them to you.
When does most pregnancy weight gain happen?
Most weight gain happens in the second and third trimesters. During the first trimester, most people gain only 1 to 5 pounds total, and some lose a little due to nausea. After that, about half a pound to one pound per week is typical through the rest of pregnancy.
Where does pregnancy weight gain go?
It is spread across baby (7 to 8 pounds), placenta (1 to 2 pounds), amniotic fluid (2 pounds), uterus growth (2 pounds), increased blood volume (3 to 4 pounds), breast tissue (1 to 3 pounds), fat stores for delivery and breastfeeding (6 to 8 pounds), and extra fluid (2 to 3 pounds).
How does a pregnancy weight gain calculator work?
It takes your height and pre-pregnancy weight, works out your BMI, and matches it to the IOM range for that BMI. The tracker then plots your weekly weigh-ins against that range so you can see the trend, which matters more than any single number.