Pregnancy Weight Gain Calculator

Track your gestational weight schedule. Compares weight changes week-by-week against the Institute of Medicine (IOM) guidelines.

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Calculate Weight Gain

Enter your height, pre-pregnancy weight, current weight, and gestational week on the left to review your weight gain trajectory.

1. Importance of Tracking Gestational Weight Gain

Tracking weight gain during pregnancy is an important aspect of monitoring maternal and fetal health. The ideal amount of weight gain varies for each individual and depends on several factors, including your **pre-pregnancy BMI**.

Gaining weight within recommended ranges helps support a healthy pregnancy and reduce potential gestational risks. You can calculate your baseline body mass index using our BMI Calculator.

2. Institute of Medicine (IOM) Weight Guidelines

The Institute of Medicine (IOM) recommends weight gain targets based on pre-pregnancy BMI categories:

  • Underweight (BMI < 18.5): Recommended gain of 28 to 40 lbs (12.7 to 18.1 kg).
  • Normal Weight (BMI 18.5-24.9): Recommended gain of 25 to 35 lbs (11.3 to 15.9 kg).
  • Overweight (BMI 25.0-29.9): Recommended gain of 15 to 25 lbs (6.8 to 11.3 kg).
  • Obese (BMI >= 30.0): Recommended gain of 11 to 20 lbs (5.0 to 9.1 kg).

3. Week-by-Week Weight Gain Curves

Weight gain typically progresses at different rates across trimesters:

  • First Trimester (Weeks 1-12): Minimal weight gain is typical (approx. 1 to 4.5 lbs overall).
  • Second and Third Trimesters (Weeks 13-40): Steady weight gain occurs as the fetus develops. Normal weight individuals typically gain about 1 lb per week, while overweight and obese individuals typically gain about 0.5 to 0.6 lbs per week.

4. Gestational Hydration, Macros, and Energy Needs

Staying adequately hydrated is essential during pregnancy to support metabolic adaptations and amniotic fluid volume. Track your daily hydration targets with our Water Intake Calculator. Consult with your healthcare provider to adjust your caloric targets. You can estimate your baseline daily needs with our TDEE Calculator and plan nutrient distributions using our Macro Calculator.