About this tool
How much weight should you gain in pregnancy? It depends on your BMI before you were pregnant. The calculator uses the Institute of Medicine 2009 guidelines - the reference used in prenatal care - to show the total recommended gain for a single baby, the weekly pace in the second and third trimesters and the range for the week you are in now. Add your current weight to see whether your gain is below, within or above that range on a chart from week 0 to 40. An estimate for information; your prenatal team sets your own target. Calculated in your browser.
How to use it
- 1 Type your weight before pregnancy and your height.
- 2 Set the week of pregnancy you are in.
- 3 Optionally add your current weight.
- 4 Read the range for this week, the total for the pregnancy and where you are on the chart.
Frequently asked questions
How much weight should I gain in pregnancy?
For a single baby: 12.5–18 kg if your BMI before pregnancy was under 18.5; 11.5–16 kg for 18.5–24.9; 7–11.5 kg for 25–29.9; and 5–9 kg for 30 or more (Institute of Medicine, 2009).
How much in the first trimester?
Usually little: about 0.5 to 2 kg in the first 13 weeks. Most of the gain happens in the second and third trimesters.
And with twins?
Twin pregnancies have higher targets and depend more on individual follow-up: ask your prenatal team.
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