Pregnancy Weight Gain Calculator
Find your recommended pregnancy weight gain range based on pre-pregnancy BMI.
Assumptions used in this calculation
- IOM guidelines: Based on singleton pregnancies; twin/multiple pregnancies have different guidelines not covered here.Institute of Medicine (2009) pregnancy weight gain guidelines
About this calculator
Pregnancy weight gain guidance isn't one-size-fits-all, the healthy total range depends on your pre-pregnancy BMI category, and figuring out both that starting category and the appropriate range from Institute of Medicine (IOM) tables takes cross-referencing two separate lookups. This calculator does both steps for you: enter your pre-pregnancy height and weight to compute your starting BMI category, then it returns the IOM-recommended total weight gain range for that category, plus an expected gain-to-date figure based on your current week of pregnancy, since gain isn't linear across all 40 weeks. Someone who started pregnancy underweight is guided toward a higher total gain than someone who started at a higher BMI, reflecting different nutritional starting points rather than a single universal target. This is based on singleton-pregnancy IOM guidelines; twin and multiple pregnancies follow separate, higher recommendations not covered here, so consult your doctor for those specific ranges.
Worked example
165 cm, 65 kg pre-pregnancy, week 30
Result: Recommended total gain: 11.5-16 kg
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