Comprehensive Calculator Guide
This calculator gives the healthy range of weight to gain over a pregnancy, based on your BMI before pregnancy and the 2009 Institute of Medicine guidelines. A woman of 60 kg and 165 cm has a BMI of 22, so the recommended gain is 11.5 to 16 kg. The ranges are for a single baby.
The ranges by BMI
Underweight (below 18.5): 12.5–18 kg. Normal (18.5–24.9): 11.5–16 kg. Overweight (25–29.9): 7–11.5 kg. Obese (30 or more): 5–9 kg. The gain covers the baby, placenta, fluid, extra blood and some fat stores for breastfeeding.
Twins, gestational diabetes, high blood pressure and teenage pregnancy need individual advice. Dieting to lose weight during pregnancy is not advised without medical supervision.
How to Use
- 01Enter your weight before pregnancy, not your current weight.
- 02Enter your height.
- 03Read your pre-pregnancy BMI and the recommended gain.
Formula Used
BMI < 18.5: 12.5–18 kg | 18.5–24.9: 11.5–16 | 25–29.9: 7–11.5 | ≥ 30: 5–9Practical Examples
Example 1
60 kg, 165 cm: BMI 22.0, gain 11.5–16 kg.
Example 2
80 kg, 160 cm: BMI 31.2, gain 5–9 kg.
Important Tips
- Weigh yourself weekly and share the record with your doctor.
Common Mistakes to Avoid
- Using current weight instead of pre-pregnancy weight.
- Applying these ranges to twins.
Frequently Asked Questions
- How much weight should I gain?
- 11.5–16 kg if your BMI was normal before pregnancy.
- What if I was overweight?
- 7–11.5 kg for BMI 25–29.9, 5–9 kg for 30 or more.
- What about twins?
- The ranges are higher; ask your doctor.