Pregnancy Weight Gain Calculator
Enter pre-pregnancy weight, height and current week to estimate the recommended total and current-week weight gain (kg).
Input Data
Results
At a glance:Total gain by pre-pregnancy BMI using IOM ranges; current-week cumulative gain is estimated linearly from total (actual gain is not perfectly linear).
Formula
bmi = preWeightKg / (heightCm/100)^2.
Total gain: underweight(BMI<18.5) 12.5-18kg; normal 11.5-16kg; overweight(25-29.9) 7-11.5kg; obese(>=30) 5-9kg.
Week cumulative = total x week / 40.
How to Use
- Enter pre-pregnancy weight (kg), height (cm) and current gestational week.
- Get pre-pregnancy BMI, total gain range and current-week suggested gain.
Case Studies
60kg / 165cm / week 20
BMI = 60/1.65^2 ~ 22.0 (normal); total gain 11.5-16kg.
Week-20 cumulative ~5.8-8.0kg.
FAQ
Why split by pre-pregnancy BMI?
Underweight women need more gain to support fetal growth; obese women should limit gain to reduce complication risk.
Does this apply to twins?
No; multiples need higher ranges - consult your physician.
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References
Content reviewed by the Calculatorism editorial team. Results are for reference only; please refer to the relevant authorities for the official figures.