Pregnancy Weight Gain Calculator
Enter your height, pre-pregnancy weight, and current week to see your recommended pregnancy weight gain based on Institute of Medicine ranges. Your pre-pregnancy BMI sets the target, and steady gain matters more than any single week.
How the ranges are set
The Institute of Medicine ties recommended pregnancy weight gain to your pre-pregnancy body mass index (BMI). People who start at a lower BMI are advised to gain more, and those who start at a higher BMI to gain less, because the goal is healthy growth for the baby with the lowest risk for both of you.
Most of the gain happens after the first trimester. Early on, gain is small (often 1 to 4.5 pounds total), then it becomes a fairly steady weekly amount. This tool estimates roughly how much you would have gained by your current week for a single pregnancy; twin ranges are higher and less standardized, so confirm yours with your provider.
Related questions
- How much weight should I gain in pregnancy?
- It depends on your pre-pregnancy BMI: about 28 to 40 lb if underweight, 25 to 35 lb at a healthy weight, 15 to 25 lb if overweight, and 11 to 20 lb if obese, for a single baby. Twin pregnancies have higher ranges.
- What if I am gaining too fast or too slowly?
- Talk to your provider rather than changing your diet sharply on your own. They look at your trend over time, not a single week, and will adjust guidance based on your health and the baby growth.
- Is the weekly estimate exact?
- No. It is a rough guide for a single pregnancy assuming steady gain after the first trimester. Real gain varies week to week, which is normal. Your provider tracks the overall pattern.
Sources & further reading
ParentFlow: one free app, newborn to age six
ParentFlow is a free baby tracker that logs feeds, sleep, diapers, pumping and growth in one tap, with your daily summary, trends, and reminders based on your own logs. Free for everyday tracking on iPhone, Android, and the web.
App Store Google Play Open Web AppThis tool gives general estimates for education only and is not medical advice or a diagnosis. Your provider sets your individual weight goal based on your health; these are general ranges. For your own care, contact your healthcare provider.