How much should I gain each week?

After the first trimester, about 0.35–0.5 kg (0.75–1 lb) a week for a normal BMI and one baby.

Does the range change for twins?

Yes. Tick "Expecting twins" for the twin guidance.

What if I'm gaining more or less?

Talk to your midwife or doctor. Individual advice depends on your health.

Pregnancy Weight Gain Calculator

Enter your height, pre-pregnancy weight, current weight and week to compare your gain with Institute of Medicine guidelines.

Your Details

Height (cm)

Pre-pregnancy weight (kg)

Current weight (kg)

Current week

Recommended total weight gain in pregnancy from pre-pregnancy BMI, with weekly rates by trimester and twin-pregnancy ranges.

Formula

Institute of Medicine 2009: underweight 12.5–18 kg, normal 11.5–16, overweight 7–11.5, obese 5–9 (singleton); higher ranges for twins.

Reference Values

•Most gain occurs in the 2nd/3rd trimesters
•Normal BMI rate: ~0.35–0.5 kg/week
•Pre-pregnancy BMI sets the category

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FAQ

Common questions about Pregnancy Weight Gain Calculator

How we calculate this

We use the standard published formula for this calculation, and we show the working so you can check it.

Spotted a mistake? Tell us and we'll check it within a few days. See how we check our calculators.

Medical disclaimer

This tool gives a general estimate for information only. It is not medical advice and cannot diagnose a condition. Talk to a doctor, midwife or other qualified professional about your own situation.