Pregnancy Weight Gain Calculator

This calculator is a useful way for you to keep tabs on the weight you should be gaining as you move through your pregnancy. It offers a weekly guide for appropriate weight gain. However, please keep in mind that the figures given are approximations of suitable weight gain, so don't be too concerned if you gain weight at a slightly quicker or slower rate than indicated.

Using the calculator

To use the calculator, first enter whether you would like to give and receive all values as imperial or metric measurements. Then, in the boxes specified, enter your height and your weight prior to falling pregnant. Next, input your weight at present, followed by whether you are expecting multiple births (e.g. twins), as this will affect how much weight you gain. Finally, select how many weeks into your pregnancy you are.

Pregnancy Weight Gain Calculator


Weight gain during pregnancy is not only healthy but vital as the fetus, uterus, amniotic fluid and placenta must all increase in volume to ensure a healthy birth. In short, suitable weight gain supports the growth of your baby.

A number of factors impact the amount of weight you will gain as your pregnancy continues, for example, your BMI and whether you are expecting a single birth or multiple births. Below is a pregnancy weight gain table to use as a guide.

BMI Before Pregnancy Category Recommended Weight Gain Range
Pregnancy with Single Child
Recommended Weight Gain Range
Pregnancy with Twins
<18.5 kg/m2 Under Weight 28 - 40 lbs
13 - 19 kg
18.5 - 24.9 kg/m2 Normal Weight 25 - 35 lbs
11 - 16 kg
37 - 54 lbs
17 - 25 kg
25 - 29.9 kg/m2 Over Weight 15 - 25 lbs
7 - 11 kg
31 - 50 lbs
14 - 23 kg
>30 kg/m2 Obese 11 - 20 lbs
5 to 9 kg
25 - 42 lbs
11 to 19 kg

In the first trimester of your pregnancy, it is typical to put on just three or four pounds. This is because the fetus remains extremely small. Furthermore, morning sickness is common during this time and may stop you gaining anything. The second trimester is when you will put on the most weight. Weight gain will then continue but slow during the final trimester, being minimal in your final month.

This calculator was created using the pregnancy weight gain distribution recommendations provided by the Institute of Medicine of the National Academies.1 Thus, it helps you effectively track your weight gain during pregnancy and determine whether you are within medically-recommended parameters.

1. Institute of Medicine and National Research Council. (2009). Weight Gain During Pregnancy: Reexamining the Guidelines. Washington, DC: The National Academies Press.

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