How much weight should I gain during pregnancy?

It depends on your pre-pregnancy BMI. For normal-weight women (BMI 18.5–24.9), the IOM recommends 11.5–16 kg (25–35 lb) total.

Is the weight gain the same for twins?

No. Twin pregnancies typically require more weight gain. The IOM has separate guidelines for multiple pregnancies.

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Pregnancy Weight Gain Calculator

Estimate the recommended weight gain during pregnancy based on your pre-pregnancy BMI and current week.

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About Pregnancy Weight Gain

Gaining an appropriate amount of weight during pregnancy supports the health of both mother and baby. This calculator uses the Institute of Medicine (IOM) 2009 guidelines to estimate a healthy weight gain range.

How it works

Your pre-pregnancy BMI determines your weight category, which in turn determines the recommended total gain and weekly rate. During the first trimester, weight gain is usually modest (about 0.5–2 kg total). From the second trimester onward, the rate increases and stays relatively steady.

IOM recommendations (singleton)

Underweight (BMI < 18.5): 12.5–18 kg (28–40 lb)
Normal weight (BMI 18.5–24.9): 11.5–16 kg (25–35 lb)
Overweight (BMI 25–29.9): 7–11.5 kg (15–25 lb)
Obese (BMI ≥ 30): 5–9 kg (11–20 lb)

Twin pregnancies

For twin pregnancies, the recommended ranges are higher. The calculator adjusts automatically when you select "Yes" for twins.

Important notes

Weight gain can vary significantly from person to person. Factors like morning sickness, fluid retention, and individual metabolism all play a role. These ranges are general guidance — your healthcare provider can give you personalized advice.