Pregnancy Weight Gain Calculator
Track healthy maternal weight gain by gestational week based on Institute of Medicine (IOM) pre-pregnancy BMI guidelines.
Pre-pregnancy baseline weight
Your weight today
Pre-Pregnancy BMI
21.6
Normal Weight
Total Recommended (Full Term)
25 – 35 lbs
Single baby
Week 24 Target Range
9.8 – 15.3 lbs
At current stage
Gain Status
On Track
12.0 lbs gained
Medical & Prenatal Health Disclaimer: Weight gain patterns naturally fluctuate from week to week. These estimations are based on the standard Institute of Medicine (IOM) clinical guidelines for singleton and twin pregnancies. Never attempt restrictive dieting or sudden weight changes during pregnancy without direct guidance from your OB-GYN or licensed midwife.
What is Pregnancy Weight Gain Calculator?
The Pregnancy Weight Gain Calculator computes healthy weight gain targets for expecting mothers based on pre-pregnancy Body Mass Index (BMI), current gestational week, and singleton or twin pregnancy. Adhering to Institute of Medicine (IOM) clinical guidelines, it helps ensure optimal maternal and fetal health.
Designed for accuracy, speed, and privacy, this tool runs entirely on your local device with zero network latency.
How to Use the Pregnancy Weight Gain Calculator
- 1Select your measurement unit: Imperial (feet, inches, lbs) or Metric (cm, kg).
- 2Enter your height and pre-pregnancy weight to calculate your baseline pre-pregnancy BMI category.
- 3Enter your current gestational week (1 to 40) and current weight.
- 4Toggle the "Twins Pregnancy" checkbox if expecting multiples to adjust target gain curves.
- 5Inspect your target total weight gain range and trimester-specific trajectory breakdown.
Formula & Calculation Logic
Applies the National Academy of Medicine (Institute of Medicine) weight gain guidelines: Underweight (<18.5 BMI) 28–40 lbs; Normal (18.5–24.9 BMI) 25–35 lbs; Overweight (25–29.9 BMI) 15–25 lbs; Obese (>=30 BMI) 11–20 lbs.
Target_Gain(Week) = 1st_Trimester_Gain + ((Week - 13) * Weekly_Rate_2nd_3rd_Trimester)Pregnancy Weight Gain Calculator Frequently Asked Questions
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