Pregnancy Weight Gain Calculator
Calculate recommended weight gain during pregnancy based on pre-pregnancy BMI and IOM guidelines.
Input Parameters
Results
IOM Pregnancy Weight Gain Guidelines
The Institute of Medicine (IOM) recommends total weight gain based on pre-pregnancy BMI: Underweight (BMI <18.5): 12.5–18 kg | Normal (18.5–24.9): 11.5–16 kg | Overweight (25–29.9): 7–11.5 kg | Obese (≥30): 5–9 kg. Consult your doctor for personalized guidance.
What is the Pregnancy Weight Gain Calculator?
Gaining the appropriate amount of weight during pregnancy is crucial for both maternal health and fetal development. This calculator uses guidelines from the Institute of Medicine (IOM) to recommend exactly how much weight you should safely gain based on your pre-pregnancy body type.
How It Works (Formula)
The tool first calculates your pre-pregnancy Body Mass Index (BMI). Based on that classification (underweight, normal, overweight, or obese), it applies the specific weight gain target range recommended by clinical obstetricians.
$$ \text{Target Gain} = f(\text{Pre-Pregnancy BMI}) $$
For a normal BMI (18.5 - 24.9), the recommended gain is typically 25 to 35 lbs.
How to Use It
Enter your height, your weight before you became pregnant, and your current week of pregnancy. The calculator will provide a detailed chart showing your optimal weight gain trajectory from week 1 through week 40.