IOM Pregnancy Weight Gain Recommendation Calculator
Reviewed by Hamza Gujjar, Algorithm Architect & Software Developer
Last updated: July 27, 2026
Disclaimer: This calculator is provided for informational and educational purposes only and does not constitute financial, medical, legal, or other professional advice. Always consult a qualified professional before making decisions based on these results.
Weight gain targets are not one-size-fits-all
The US Institute of Medicine (now the National Academy of Medicine) publishes evidence-based total weight gain ranges for pregnancy that differ by pre-pregnancy BMI category, since nutritional needs and risk profiles vary by starting body composition.
Worked example
For a pre-pregnancy BMI of 22 (normal weight category):
Recommended Total Gain = 11.5-16.0 kg (25.4-35.3 lb)
| Pre-Pregnancy BMI Category | Recommended Total Gain |
|---|---|
| Underweight (below 18.5) | 12.5-18.0 kg |
| Normal weight (18.5-24.9) | 11.5-16.0 kg |
| Overweight (25.0-29.9) | 7.0-11.5 kg |
| Obese (30.0+) | 5.0-9.0 kg |
These ranges apply to singleton pregnancies only - twin and higher-order multiple pregnancies have separate, higher recommended ranges. This is general guidance only - always follow individualized recommendations from a qualified healthcare provider.