Pregnancy Weight Gain Calculator
Map pre-pregnancy height and weight to IOM gestational weight-gain ranges. Choose singleton or twins tables and optionally compare a gain in pounds. Informational, not prenatal care or medical advice.
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How to read pregnancy weight-gain ranges
- Choose metric or US units for height and pre-pregnancy weight.
- Enter height and the weight from before pregnancy.
- Select singleton or twins ranges (values false or true).
- Optionally enter total gain in pounds to compare with the listed band.
- Follow clinician targets over any web table. Nothing is uploaded.
Gestational weight-gain range
IOM bands from pre-pregnancy BMI
| BMI input | Pre-pregnancy height and weight |
|---|---|
| Singleton example | Normal BMI: 25 to 35 lb total |
| Twins example | Normal BMI twins: 37 to 54 lb total |
| Weekly sketch | Second and third trimester lb/week hints |
| Optional compare | gainLb versus total range |
| Advice | Informational. Not prenatal care. |
What the IOM ranges describe
Institute of Medicine / National Academies tables link pre-pregnancy BMI categories to total pregnancy weight-gain ranges. Twins use wider bands. This page looks up those published sketches; it does not personalize for comorbidities.
How the category is chosen
Pre-pregnancy BMI = kg / m2. Underweight (<18.5), normal (18.5-24.9), overweight (25-29.9), and obesity (30+) each map to a singleton or twins gain band with an approximate weekly rate for later trimesters. Optional gainLb is compared with the total band only.
Pregnancy sizing and calendar tools
Entities include pre-pregnancy BMI, IOM category, and gain range. Due dating lives on pregnancy due date. Conception calendar sketches sit on pregnancy conception. General BMI is BMI.
Use cases
Seeing which published band matches a pre-pregnancy BMI. Comparing singleton and twins tables side by side. Classroom review of IOM categories. Not a substitute for obstetric counseling.
Default numbers
At 165 cm and 60 kg, BMI ≈ 22.0 (normal). Singleton total gain lists 25 to 35 lb with about 1.0 lb/week in later trimesters. Twins for the same BMI lists 37 to 54 lb.
Limits
Multiples beyond twins, adolescents, and medical diet restrictions need clinician plans. Weekly rates are sketches, not mandates. Informational only. See the disclaimer. CZNull does not receive pregnancy data.