Weight gain is a vital part of pregnancy. Use our tool to calculate your pre-pregnancy BMI and determine your recommended healthy weight gain range.
The BMI measurement before pregnancy is a baseline used to calculate how much weight a woman should gain to ensure a healthy environment for the fetus. Excessive or insufficient weight gain can increase risks for both mother and child.
| Category | Pre-Pregnancy BMI | Recommended Gain |
|---|---|---|
| Underweight | Less than 18.5 | 12.5 – 18 kg |
| Normal Weight | 18.5 – 24.9 | 11.5 – 16 kg |
| Overweight | 25.0 – 29.9 | 7.0 – 11.5 kg |
| Obese | 30.0 or more | 5.0 – 9.0 kg |
If you are expecting twins, the weight gain recommendations are higher. Typically, a woman with a normal pre-pregnancy BMI should gain between 17 and 25 kg. This extra mass supports the growth of both infants and the expansion of the placenta and amniotic fluid.
Weight gain should be gradual. In the first trimester, very little weight gain (0.5 – 2 kg) is expected. During the second and third trimesters, a gain of about 0.5 kg per week is standard for those in the normal BMI range.