Pregnancy Weight Gain Calculator

Estimate healthy weight gain ranges during pregnancy based on IOM guidelines.

Pre-Pregnancy
Current Pregnancy

Select units, enter pre-pregnancy and current details.

Guidelines based on Institute of Medicine (IOM) recommendations. Individual needs may vary. Always discuss weight gain with your healthcare provider.

Healthy Pregnancy Weight Gain Guidelines

Gaining an appropriate amount of weight during pregnancy is important for both the mother's and the baby's health. Recommendations for weight gain are based on the mother's pre-pregnancy Body Mass Index (BMI). Gaining too little or too much weight can increase risks for certain complications.

This calculator uses the guidelines established by the Institute of Medicine (IOM) to estimate a healthy weight gain range throughout pregnancy.

How to Use

  1. Select Metric or Imperial units.
  2. Enter your **pre-pregnancy** weight and height.
  3. Enter the current week of your pregnancy (1-42).
  4. Select the pregnancy type (Singleton or Twins). Guidelines differ.
  5. Click "Calculate Weight Gain Range".

The results will show your calculated pre-pregnancy BMI category, the total recommended weight gain range for your entire pregnancy based on that BMI and pregnancy type, and the estimated healthy weight gain range up to your current week of pregnancy.

IOM Guidelines (Singleton Pregnancy)

Recommendations based on pre-pregnancy BMI:

  • Underweight (BMI < 18.5): 28-40 lbs (12.5-18 kg) total gain.
  • Healthy Weight (BMI 18.5-24.9): 25-35 lbs (11.5-16 kg) total gain.
  • Overweight (BMI 25.0-29.9): 15-25 lbs (7-11.5 kg) total gain.
  • Obesity (BMI ≥ 30.0): 11-20 lbs (5-9 kg) total gain.

Guidelines for twins are higher and also based on pre-pregnancy BMI.

The calculator typically estimates weekly gain rates (lower in the first trimester, higher in the second and third) to determine the recommended range for the current week.

Importance of Healthy Weight Gain

  • Supports fetal growth and development.
  • Helps prepare the mother's body for birth and breastfeeding.
  • Reduces risks of complications like gestational diabetes, hypertension, premature birth, and cesarean delivery.
  • Contributes to a healthy birth weight for the baby.

Crucially, these are guidelines, not strict rules. Your individual weight gain target should be discussed and monitored with your doctor or midwife, considering your specific health status and needs. Focus on a balanced diet and appropriate activity levels as advised by your healthcare provider.