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Pregnancy calculator

Pregnancy Weight Gain Calculator

Compare current pregnancy weight gain with guideline ranges based on pre-pregnancy BMI.

Use this as a conversation aid for prenatal care, not as a diagnosis. Individual recommendations can differ.

Method

The calculator classifies pre-pregnancy BMI and uses Institute of Medicine/CDC pregnancy weight-gain ranges. Current-week estimates assume about 1.1-4.4 lb in the first trimester and guideline weekly gain after week 13.

Example

If pre-pregnancy weight was 65 kg, current weight is 72 kg and height is 165 cm at week 24, pre-pregnancy BMI is about 23.9 and current gain is 7 kg.

Common mistakes

Use pre-pregnancy weight for the BMI category, not current pregnancy weight. Twin pregnancy ranges and singleton ranges are not interchangeable.

Limitations

Pregnancy care is individual. Hyperemesis, edema, fetal growth, multiple pregnancy, diabetes, hypertension and clinician guidance can change the appropriate target.

References

Last reviewed: 2026-05-17

Before relying on this result

Use this calculator together with the formula, assumptions, limitations and examples on the page. If the topic involves health, tax, lending, investment, legal, safety or current-rate decisions, treat the number as an estimate and check the relevant primary source or professional guidance.

Calculator metadata last reviewed: 2026-05-14.