bumpcalc.comPre-pregnancy BMI
25.0
Pregnancy Weight Gain Calculator
Enter pre-pregnancy weight, height, and current week to see BMI-based total and week-by-week weight gain recommendations.
🏥 Based on IOM (Institute of Medicine) guidelines🔒 Data stays in your browser
BMI category
Normal
Total recommended gain
11.5-16.0 kg
Recommended gain by week 20
3.4-5.6 kg
Pregnancy progress: 50% of 40 weeks
Weight gain chart
- Week 12: 0.5-1.8 kg
- Week 20: 3.4-5.6 kg
- Week 28: 6.6-9.8 kg
- Week 36: 9.9-13.9 kg
- Week 40: 11.5-16.0 kg
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Frequently Asked Questions
How much weight should I gain during pregnancy?
It depends on your pre-pregnancy BMI. The IOM (Institute of Medicine) recommends: Underweight (BMI < 18.5): 28-40 lbs, Normal weight (BMI 18.5-24.9): 25-35 lbs, Overweight (BMI 25-29.9): 15-25 lbs, Obese (BMI 30+): 11-20 lbs. These are guidelines — your doctor may recommend different targets based on your individual health.
Is it OK to gain more or less than recommended?
Gaining outside the recommended range can increase certain risks. Too little gain may lead to a smaller baby, while too much can increase the risk of gestational diabetes, high blood pressure, and a larger baby. However, every pregnancy is different — discuss your specific situation with your healthcare provider.
What are the IOM weight gain guidelines?
The Institute of Medicine (IOM) published evidence-based pregnancy weight gain guidelines in 2009, which remain the standard recommendation used by healthcare providers. The guidelines are based on pre-pregnancy BMI and provide both total weight gain ranges and recommended weekly gain rates for the second and third trimesters.