Pregnancy Weight Gain Calculator

See the recommended total and week-by-week weight gain for your pre-pregnancy BMI, for a single baby or twins, and check where you stand.

Formulas last reviewed: September 2026

Enter your details

Units

Metric (kg, cm)US (lb, ft, in)

Height

Weight before pregnancy

Current weight (optional)

Current pregnancy week

weeks

Expecting twins

Recommended total weight gain

11.5 – 16 kg

Normal weight (BMI 18.5–24.9)

Expected gain by week 20

3.4 – 5.6 kg

Pre-pregnancy BMI

20.8

Week-by-week guide

Week-by-week guide
Week	Expected total gain
Week 4	0.2 – 0.6 kg
Week 8	0.3 – 1.2 kg
Week 12	0.5 – 1.8 kg
Week 16	1.7 – 3.6 kg
Week 20	3.4 – 5.6 kg
Week 24	5 – 7.7 kg
Week 28	6.6 – 9.8 kg
Week 32	8.2 – 11.9 kg
Week 36	9.9 – 13.9 kg
Week 40	11.5 – 16 kg

Based on the Institute of Medicine (2009) guidelines using WHO BMI categories. Every pregnancy is different — follow your doctor's advice, especially if your gain is outside the range.

Disclaimer: Results are general estimates for information and education only. They are not medical advice, a diagnosis or a treatment plan. Please talk to a doctor or qualified health professional before making health, diet, exercise or pregnancy decisions.

How much weight should you gain in pregnancy?

Healthy weight gain supports your baby's growth and your own health. Too little gain is linked with small babies, and too much with gestational diabetes, high blood pressure and difficult delivery.

The right amount depends on your weight before pregnancy (your BMI) and whether you are expecting one baby or twins. This calculator uses the Institute of Medicine guidelines.

How the range is worked out

BMI = pre-pregnancy weight (kg) ÷ height (m)²

First trimester: about 0.5–2 kg in total; then a steady weekly gain

The recommended total gain is set by your BMI category. The calculator spreads it across the weeks to show the range you would expect at your current week.

Worked example

60 kg before pregnancy, 162 cm, single baby, week 20

Pre-pregnancy BMI: 22.9 (normal)
Recommended total gain: 11.5 – 16 kg
Expected gain by week 20: 3.4 – 5.6 kg

Recommended total gain (one baby)

Twins: about 17–25 kg (normal BMI), 14–23 kg (overweight) and 11–19 kg (obese).

Pre-pregnancy BMI	Total gain
Under 18.5	12.5 – 18 kg
18.5 – 24.9	11.5 – 16 kg
25 – 29.9	7 – 11.5 kg
30 and above	5 – 9 kg

These ranges are general guidelines using WHO BMI categories. Indian women may need a personalised target — follow your doctor or dietitian.

Frequently asked questions

Where does the weight go?

Roughly: baby 3–3.5 kg, placenta and fluid about 1.5–2 kg, extra blood and body fluids 2–3 kg, breast and uterus growth 2 kg, and the rest is fat stores for breastfeeding.

Is it bad if I gain less?

Some women lose weight from nausea early on, which is usually fine. If your gain stays below the range, talk to your doctor about nutrition and baby growth.

Should I eat for two?

No. Extra needs are small — about 350 kcal more a day in the second trimester and 450 kcal in the third. Choose nutritious food and follow your doctor's supplements.

Is exercise safe in pregnancy?

For most healthy pregnancies, walking, prenatal yoga and gentle exercise are recommended. Check with your doctor first, especially if you have complications.