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Pregnancy Weight Gain Calculator

Find a healthy total weight gain range for your pregnancy, based on your starting BMI.

cm
kg
25-35 lb
Recommended total gain (Normal BMI)
22.0Pre-pregnancy BMI
~1 lb/wkTypical 2nd/3rd trimester rate
Ranges are based on guidelines from the Institute of Medicine (IOM), as referenced by ACOG and the CDC, for singleton pregnancies. Twin or multiple pregnancies, and individual health conditions, may need different targets, always confirm with your doctor.

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"How much weight should I gain?" is one of the most common pregnancy questions, and the honest answer depends heavily on your starting body weight, not a single universal number.

Why the Range Depends on Starting BMI

The Institute of Medicine guidelines, widely referenced by the CDC and used by many prenatal care providers, set different total weight gain ranges depending on pre-pregnancy BMI, since the health risks of gaining too much or too little differ by starting point.

The Recommended Ranges

  • Underweight (BMI under 18.5): 28-40 lb total
  • Normal weight (BMI 18.5-24.9): 25-35 lb total
  • Overweight (BMI 25-29.9): 15-25 lb total
  • Obese (BMI 30+): 11-20 lb total

These figures are for singleton pregnancies (one baby); twins or multiples typically call for a higher target range set by your doctor.

How Gain Is Usually Distributed

Most guidelines suggest a smaller gain (around 1-5 lb total) in the first trimester, followed by a steadier weekly rate through the second and third trimesters, roughly 1 lb per week for those starting at a normal BMI, and somewhat less for those starting at a higher BMI.

Pair it with

Track your pregnancy timeline with our Due Date Calculator, and if you are also tracking your cycle, our Ovulation Calculator may help too.

FAQ

Frequently Asked Questions

What if I am gaining faster or slower than the range suggests?

A single week is not a cause for concern on its own, weight gain naturally varies. Bring it up at your next prenatal appointment if it is a consistent pattern over several weeks.

Do these ranges apply to twin pregnancies?

No, twin and multiple pregnancies generally call for higher total gain targets. Your doctor will typically give you a specific range for your situation.

Is gaining less than the recommended range ever okay?

It depends on individual circumstances and should be guided by your healthcare provider, since both insufficient and excessive gain carry their own considerations for you and the baby.