Pregnancy Weight Gain Calculator
Track recommended gestational weight gain targets by trimester based on pre-pregnancy BMI.
Recommended Gain
Medical disclaimer. This calculator is for general information and education only. It is not medical advice, not a diagnosis, and not a substitute for professional care. Ranges follow the Institute of Medicine guidance for singleton pregnancies. Your own target should come from your antenatal care, particularly with a multiple pregnancy, gestational diabetes or a pre-existing condition.Speak to a doctor or another qualified clinician about any health decision.Last reviewed .
Frequently asked questions
How much weight should I gain during pregnancy?
Recommended pregnancy weight gain depends on pre-pregnancy BMI: Normal weight (11.5 - 16 kg), Underweight (12.5 - 18 kg), Overweight (7 - 11.5 kg).
How much weight should I gain during pregnancy?
The Institute of Medicine recommends gain by pre-pregnancy BMI: 12.5-18 kg if underweight (BMI under 18.5), 11.5-16 kg if normal weight, 7-11.5 kg if overweight, and 5-9 kg if obese. Twin pregnancies have separate, higher ranges. Your own clinician's advice supersedes any general guideline.
How is the gain distributed across the pregnancy?
Gain in the first trimester is typically small - around 0.5-2 kg - with most accumulating in the second and third trimesters at roughly 0.4 kg per week for someone starting at a normal BMI. Steady gain matters more than hitting a weekly number exactly.
Where does the weight actually go?
At term, roughly 3-3.5 kg is the baby, about 0.9 kg placenta, 0.9 kg amniotic fluid, 0.9 kg uterus, 0.5-1.4 kg breast tissue, 1.4-1.8 kg increased blood volume, and the remainder maternal fat stores that support breastfeeding. Only a fraction of pregnancy gain is maternal fat.