BMI-based
Uses your pre-pregnancy BMI category to select the public health range.
Free pregnancy calculator
Pregnancy Weight Gain Calculator
A pregnancy weight gain calculator estimates a broad target range based on pre-pregnancy BMI, current pregnancy week, and whether you are carrying one baby or twins. Use it as an educational starting point, then follow your prenatal care team's personalized guidance.
Your pregnancy weight gain estimate
Enter your height, pre-pregnancy weight, pregnancy type, and week to see a BMI-based range.
Weight gain ranges by pre-pregnancy BMI
| BMI category | BMI | One baby | Twins |
|---|---|---|---|
| Underweight | Less than 18.5 | 28-40 lb | 50-62 lb |
| Normal weight | 18.5-24.9 | 25-35 lb | 37-54 lb |
| Overweight | 25-29.9 | 15-25 lb | 31-50 lb |
| Obese | 30.0 or higher | 11-20 lb | 25-42 lb |
These are broad CDC/IOM ranges. If you are pregnant with triplets or more, have gestational diabetes, severe nausea, swelling, a prior pregnancy complication, or a clinician-provided target, use your care team's guidance instead.
Twin option
Switch between one baby and twins to see the correct total range.
Week-by-week context
Compare optional current gain with a simple estimate for your selected week.
Guidance used by this calculator
The calculator uses CDC pregnancy weight gain tables for people carrying one baby or twins, which are based on pre-pregnancy BMI categories. The CDC also notes that people pregnant with triplets or more should talk with a health care provider about personalized weight gain goals.
General ranges do not account for your medical history, appetite changes, fluid retention, fetal growth pattern, or conditions such as gestational diabetes. Bring questions about weight trends to your prenatal appointments.
Frequently Asked Questions
How much weight should I gain during pregnancy?
General pregnancy weight gain targets are based on your pre-pregnancy BMI and whether you are carrying one baby or twins. For one baby, CDC/IOM ranges are 28-40 lb for underweight, 25-35 lb for normal weight, 15-25 lb for overweight, and 11-20 lb for obesity.
How does BMI affect pregnancy weight gain?
Pre-pregnancy BMI is used to group weight gain targets because baseline body weight changes the amount of additional gain associated with healthier birth outcomes. BMI is a screening tool, not a diagnosis, so your clinician may personalize your goal.
How much weight should I gain each week?
Most people gain only a small amount in the first trimester. After that, a common weekly pace is about 1-1.3 lb for underweight, 0.8-1 lb for normal weight, 0.5-0.7 lb for overweight, and 0.4-0.6 lb for obesity when carrying one baby.
Are twin pregnancy weight gain ranges different?
Yes. CDC lists higher total ranges for twin pregnancies: 50-62 lb for underweight, 37-54 lb for normal weight, 31-50 lb for overweight, and 25-42 lb for obesity. Triplets or more require individualized clinician guidance.
Is this calculator medical advice?
No. This calculator is an educational estimate based on broad public health ranges. Your prenatal care team should set your personal goal, especially if you have nausea, gestational diabetes, swelling, a high-risk pregnancy, or a history of complications.
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