About this Calculator
A healthy pregnancy requires appropriate weight gain to support the development of your baby, placenta, and amniotic fluid. This calculator estimates your target weight gain range based on your pre-pregnancy BMI.
Formula & Calculations
Mathematical Formula
IOM Pregnancy Weight Gain Target Ranges
Target guidelines are based on pre-pregnancy BMI classification.
How to Calculate Step-by-Step
1
Calculate pre-pregnancy BMI
Determine weight category class.
2
Determine twin factor
Twin pregnancies require additional targets.
3
Evaluate week targets
Track weekly progression scale.
How to Use & Best Practices
Input your height, pre-pregnancy weight, current weight, and week of pregnancy.
Frequently Asked Questions
How much weight should I gain in the first trimester?
Typically only 1 to 5 lbs (0.5 to 2.3 kg) total.