Pregnancy Weight Gain Calculator
Your pre-pregnancy BMI, the recommended total gain for one baby or twins, and the weight range that puts you at by delivery.
Recommended total gain
—
Extra calories (CDC): about 0 in the first trimester, +340/day in the second, +450/day in the third.
The table (CDC / Institute of Medicine 2009)
| Before pregnancy | One baby | Twins |
|---|---|---|
| Underweight · BMI under 18.5 | 28–40 lb | 50–62 lb* |
| Normal weight · 18.5–24.9 | 25–35 lb | 37–54 lb |
| Overweight · 25.0–29.9 | 15–25 lb | 31–50 lb |
| Obese · 30.0–39.9 | 11–20 lb | 25–42 lb |
* Underweight with twins: from Luke et al. 2003, as noted by CDC.
Common questions
How much weight should I gain during pregnancy?
It depends on your BMI before pregnancy. For one baby, CDC (citing the Institute of Medicine): 28–40 lb if underweight, 25–35 lb at a normal weight, 15–25 lb if overweight, 11–20 lb with obesity.
What about twins?
37–54 lb at a normal weight, 31–50 lb if overweight, 25–42 lb with obesity. For underweight women with twins, CDC's 50–62 lb figure comes from a separate study (Luke 2003), not the IOM.
Do I need to eat more?
CDC: generally no extra calories in the first trimester, about 340 more a day in the second and about 450 more in the third.
My BMI is 40 or higher — which row applies?
CDC's table lists obesity as BMI 30.0–39.9. Ask your clinician for a target if your BMI is 40 or above.
How it's computed
Pre-pregnancy BMI = kg ÷ m², then the matching CDC row. Kilograms = lb ÷ 2.2046. Target weight = your pre-pregnancy weight + the range.
Sources
- CDC — Weight gain during pregnancy (Institute of Medicine 2009 recommendations, singleton and twins). www.cdc.gov