You can use your BMI (body mass index) to find out how much weight you should be gaining during pregnancy. Your heath care provider may refer to your BMI when recommending a certain diet or weight gain pattern. You can use this BMI tool on the National Heart, Lung, and Blood institute’s website to determine your BMI.

BMI is scored between 18 and 30, with the “ideal” BMI between 20 and 25. If you are underweight, it’s recommended that you gain between 28 to 40 pounds during pregnancy. If average-sized, plan on gaining around 25 to 35 pounds during pregnancy. And if you’re overweight, it’s advised that you gain only 15 to 25 pounds during pregnancy.