Important: These ranges are population-level recommendations and aren't individualized medical advice. Talk with your OB/GYN or midwife about your personal weight-gain goals.
Log your weight
How is pregnancy weight gain calculated?
Recommended pregnancy weight gain is based primarily on your pre-pregnancy BMI, whether you're carrying a singleton or twins, and your stage of pregnancy. These guidelines come from the Institute of Medicine (IOM), which studied outcomes across a large population to identify gain ranges associated with healthy pregnancies.
Your pre-pregnancy BMI places you into one of four categories, each with a different recommended range — lower BMI categories are generally advised to gain more, and higher BMI categories less, since starting weight already factors into overall pregnancy weight:
Underweight (BMI under 18.5)28–40 lb
Normal weight (BMI 18.5–24.9)25–35 lb
Overweight (BMI 25–29.9)15–25 lb
Obese (BMI 30+)11–20 lb
Most of this gain happens in the 2nd and 3rd trimesters, following a fairly steady weekly rate, while first-trimester gain is typically minimal. Not sure of your pre-pregnancy BMI? Use the BMI Calculator first, then come back here.
Frequently asked questions
It depends on your pre-pregnancy BMI. Guidelines range from 28–40 lb for underweight individuals down to 11–20 lb for those in the obese BMI category — see the exact range for your category above.
Yes, significantly — recommended ranges for twin pregnancies are noticeably higher than singleton pregnancies across every BMI category, which is why there's a separate toggle for it.
Most weight gain happens in the second and third trimesters. First-trimester gain is typically minimal — often just 1 to 4.5 lb total.
These are population-level guidelines, not a strict target — some healthy pregnancies vary from them. Bring up any concerns about your rate of gain with your OB or midwife, who can factor in your specific situation.
They're general recommendations from the Institute of Medicine (IOM) based on population data — your OB or midwife may recommend something different based on your individual health history.
Yes — after calculating your range, use "Log your weight" to save your weight at each pregnancy week. You'll see whether your cumulative gain is tracking within, above, or below the recommended range for that week.
Yes — week-to-week weight can fluctuate with water retention, digestion, and measurement timing. What matters more is the overall trend over several weeks, not any single week's number.
Figures reflect standard Institute of Medicine (IOM) guidelines. Individual needs vary by health history, multiples, and other factors your care provider will account for.