🤰Pregnancy Weight Gain Calculator

About this tool

Enter your weight before pregnancy, your height, your weight now and the week of pregnancy, in kilograms and centimetres or pounds and inches. Tick the box if you are expecting twins. The calculator shows your pre-pregnancy BMI, the recommended total gain, the range for your current week, your gain so far and a chart of the recommended band by week.

How much weight to gain in pregnancy

The ranges come from the US Institute of Medicine's 2009 guidelines, which many countries use. They depend on your BMI before pregnancy: 12.5–18 kg for underweight, 11.5–16 kg for a healthy weight, 7–11.5 kg for overweight and 5–9 kg for obese. Twin pregnancies have higher ranges: 17–25 kg, 14–23 kg and 11–19 kg, with no set range for underweight. Most of the gain comes after the first trimester. The weekly band here assumes 0.5–2 kg by the end of week 13, then steady gain to the total range at week 40. Someone who weighed 65 kg at 165 cm had a BMI of 23.9 before pregnancy, so the total range is 11.5–16 kg. At week 24 the band is about 5.0–7.7 kg, and weighing 71 kg now, a gain of 6 kg, sits within it. Gaining a little outside the band is common and is not a diagnosis. Honest limits: guidance differs between countries, and the UK's NICE does not set target ranges. Your midwife or doctor will give advice that fits you. Never diet to lose weight in pregnancy without medical advice. Not medical advice. The due date calculator works out your week, the BMI calculator explains the categories and the water intake calculator covers hydration. Is BMI accurate? discusses BMI's limits.

Frequently asked questions