Pregnancy Weight Gain Calculator
Find out how much weight you should gain during pregnancy based on your pre-pregnancy BMI, following IOM (Institute of Medicine) guidelines.
Calculate Your Recommended Weight Gain
Understanding Pregnancy Weight Gain
Gaining the right amount of weight during pregnancy is important for both your health and your baby's development. Too little weight gain can lead to a low birth weight baby, while too much can increase the risk of gestational diabetes, high blood pressure, and complications during delivery.
IOM Weight Gain Recommendations
| BMI Category | BMI Range | Recommended Gain |
|---|---|---|
| Underweight | < 18.5 | 12.5 - 18 kg |
| Normal weight | 18.5 - 24.9 | 11.5 - 16 kg |
| Overweight | 25 - 29.9 | 7 - 11.5 kg |
| Obese | ≥ 30 | 5 - 9 kg |
Frequently Asked Questions
About the Author
Due Date Calculator SA Editorial Team
Our content is reviewed by healthcare professionals familiar with South African maternal health practices. We combine evidence-based medical information with local knowledge to support South African mums throughout their pregnancy journey. Our team includes contributors with backgrounds in midwifery, obstetrics, and maternal health education.
Last reviewed: February 2026