Pregnancy Weight Gain Calculator UK
Find out how much weight you might expect to gain during pregnancy, based on NICE guidelines and your pre-pregnancy BMI. Supports single and multiple pregnancies.
Enter your pre-pregnancy height and weight to see the recommended weight gain range based on NICE guidelines.
Pre-pregnancy height in centimetres
Pre-pregnancy weight in kilograms
NICE guidelines for pregnancy weight gain
| BMI category | BMI range | Recommended gain (single baby) |
|---|---|---|
| Underweight | Below 18.5 | 12.5 to 18 kg |
| Healthy weight | 18.5 to 24.9 | 11.5 to 16 kg |
| Overweight | 25 to 29.9 | 7 to 11.5 kg |
| Obese | 30 or above | 5 to 9 kg |
For twin pregnancies, add approximately 50% to the recommended range. Always discuss weight gain with your midwife, as individual circumstances vary.
Where does the weight go?
Weight gain during pregnancy is not just fat. The extra weight is made up of several components that support your baby's development and your body's needs.
- Babyapproximately 3.4 kg
- Placentaapproximately 0.7 kg
- Amniotic fluidapproximately 0.8 kg
- Increased blood volumeapproximately 1.8 kg
- Uterus growthapproximately 0.9 kg
- Breast tissueapproximately 0.9 kg
- Body fat storesapproximately 3 to 4 kg