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Pregnancy
Pregnancy Weight Gain Calculator
Get your recommended pregnancy weight gain based on pre-pregnancy BMI.
Recommended total gain
—
For your BMI.
| BMI category | — |
|---|---|
| Gain by now | — |
| Weekly rate (2nd/3rd) | — |
| Pre-pregnancy BMI | — |
Show our math
Enter your figures above to see the step-by-step working.
An estimate — not medical adviceEverything computed client-side — nothing leaves this page
How the Pregnancy Weight Gain Calculator Works
How much weight to gain in pregnancy depends on your weight before it — specifically your pre-pregnancy BMI. The Institute of Medicine guidelines recommend 25–35 lb for a normal BMI, more if you started underweight (28–40 lb) and less if overweight (15–25 lb) or obese (11–20 lb). This calculator finds your category and the target range, plus a rough figure for where you should be by your current week.
Gain is slow at first — only a few pounds in the first trimester — then steadier at around a pound a week for a normal BMI. These are averages for a single baby; twins and individual health needs differ, so follow your provider’s advice.
total gain range set by pre-pregnancy BMI (IOM guidelines)
Note: an estimate for general guidance, not medical advice. Your doctor or midwife knows your situation best.
Frequently Asked Questions
How much weight should I gain in pregnancy?
It depends on your pre-pregnancy BMI: 25–35 lb for a normal BMI, 28–40 if underweight, 15–25 if overweight, 11–20 if obese.
When does most pregnancy weight gain happen?
In the second and third trimesters, at roughly a pound a week for a normal BMI. The first trimester adds only a few pounds.
Are these figures for twins?
No — they’re for a single baby. Twin pregnancies have higher recommended ranges; ask your provider.
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