Pregnancy Weight Gain Calculator

Weight Gain Tracker

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in
Enter a week number from 1 to 40

Results

Pre-pregnancy BMI
BMI Classification
Total Recommended Gain
Target Gain for Week
Actual Gain So Far
Status

Pregnancy Weight Gain Guidelines (IOM)

Weight gain during pregnancy is necessary for fetal development, placenta growth, and amniotic fluid volume. The Institute of Medicine (IOM) recommends specific weight targets based on pre-pregnancy body composition.

IOM Target Recommendations (Single Pregnancy)

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

Weight Gain Schedule & Rate

In the first trimester (weeks 1-12), total recommended gain is generally low, around 1 to 4.5 lbs (0.5 to 2.0 kg). For the second and third trimesters, standard weekly gain rates are:

  • Underweight & Normal: ~1.0 lb/week (0.45 kg/week)
  • Overweight: ~0.6 lb/week (0.27 kg/week)
  • Obese: ~0.5 lb/week (0.23 kg/week)
Disclaimer. The recommendations generated by this calculator are based on general IOM guidelines. Healthy weight gain varies per individual. Consult with your obstetrician or midwife for a customized nutritional and health plan.