See your recommended total pregnancy weight gain and weekly pace, based on your pre-pregnancy BMI and the Institute of Medicine guidelines.
| Pre-pregnancy BMI | Total gain (singleton) |
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These ranges come from the Institute of Medicine (IOM) guidelines and are general recommendations, not targets for any individual. Twin ranges are provisional, and no IOM range exists for underweight twin pregnancies. What's right for you depends on your health and how your pregnancy is progressing. This tool is for educational purposes only and is not medical advice — your OB-GYN or midwife should guide your weight gain.
Recommended pregnancy weight gain depends mostly on your weight before pregnancy, measured as your pre-pregnancy BMI. The widely used Institute of Medicine guidelines set a total range for each BMI category: more for those who started underweight, less for those who started with a higher BMI.
The calculator works out your pre-pregnancy BMI, shows the matching total range, and estimates roughly how much gain is expected by your current week.
For a single baby, the guidelines recommend about 28 to 40 pounds if you were underweight before pregnancy (BMI under 18.5), 25 to 35 pounds for a normal BMI (18.5 to 24.9), 15 to 25 pounds if overweight (25 to 29.9), and 11 to 20 pounds if your BMI was 30 or above.
These are ranges, not single numbers, because healthy pregnancies vary. Where you fall within your range, and whether your provider adjusts it, depends on your individual situation.
Weight gain isn't even across the months. The first trimester typically adds only a few pounds — often around one to four — while most gain happens in the second and third trimesters at a steadier weekly pace. For a normal-BMI pregnancy that's roughly 0.8 to 1 pound a week in the later trimesters.
That's why the calculator separates a "by this week" estimate from the total: early on you should have gained little, with the bulk arriving later.
Carrying twins means higher recommended gain — provisionally about 37 to 54 pounds for a normal pre-pregnancy BMI, with lower ranges for higher BMIs. The guidelines note there isn't enough evidence to set a range for underweight twin pregnancies, so that case especially needs individual medical guidance.
Other situations — adolescent pregnancy, short stature, or certain health conditions — can also shift what's appropriate, which is why these numbers are a starting point for a conversation with your provider, not a rule.
Gaining within the recommended range is linked to better outcomes for both parent and baby. Gaining too little can be associated with a smaller baby, while gaining well above the range can raise the chance of complications and make postpartum weight harder to lose.
The aim isn't to hit a precise number but to stay in a healthy range while eating well and staying active as your provider advises. Don't diet to lose weight during pregnancy unless a doctor specifically recommends it.
It depends on your pre-pregnancy BMI. For a single baby, roughly 25 to 35 pounds for a normal BMI, more if you were underweight and less if you were overweight. Enter your details for your range.
Usually only a few pounds in the first trimester, then a steadier weekly gain — about 0.8 to 1 pound a week for a normal BMI — through the second and third trimesters.
More than a single pregnancy — provisionally about 37 to 54 pounds for a normal pre-pregnancy BMI, with lower ranges for higher BMIs. Twin guidance should come from your provider.
Staying in range is linked to better outcomes, but the ranges are guidance, not strict limits. Discuss any concerns with your provider rather than dieting on your own.
No — it's based on your weight before pregnancy, used to find your pre-pregnancy BMI category. That's what the IOM ranges are tied to.