CalcVind

Pregnancy Weight Gain Calculator

How much weight to gain, week by week

Before Pregnancy

weeks

General guidance only. Your doctor may advise differently.

Healthy Weight Gain

11.5 – 16 kgTotal by delivery
2.9 – 5.5 kgBy week 20
23.2 (Normal weight)
Pre-pregnancy BMI
0.35 – 0.5 kg
Weekly, from week 14
61 – 63.5 kg
Target weight now
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  1. 1
    Enter your weight before pregnancy
    And your height
  2. 2
    Add your week
    One baby or twins
  3. 3
    See healthy ranges
    Total, so far and per week

Where do the ranges come from?

The ranges follow the US Institute of Medicine's 2009 guidelines, which base healthy gain on your BMI before pregnancy. Gain is slow in the first trimester and steadier after.

BMI = weight (kg) ÷ height (m)²

First trimester: 0.5 – 2 kg; then a steady weekly gain

Why gain depends on your starting BMI

Women who start underweight are advised to gain more, and those who start overweight or obese to gain less, to lower risks for both mother and baby.

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Frequently asked questions

How much weight should I gain in pregnancy?

With a normal BMI before pregnancy, about 11.5 to 16 kg for one baby. The calculator gives your personal range.

How much weight should I gain in the first trimester?

Usually only 0.5 to 2 kg in total, since the baby is still very small.

Is this different for twins?

Yes. With a normal starting BMI, the guideline for twins is about 17 to 25 kg.

Sources

Last reviewed: October 2026