Pregnancy Weight Gain Calculator

Find the recommended total and weekly weight gain during pregnancy based on your pre-pregnancy BMI — using the 2009 Institute of Medicine guidelines.

What Does This Tool Do?

Calculate the recommended weight gain range for pregnancy based on pre-pregnancy BMI, using the 2009 Institute of Medicine (IOM) guidelines for both singleton and twin pregnancies.

Key Features

👶
IOM 2009 Guidelines
Evidence-based recommendations.
⚥
Twins Option
Separate ranges for twin pregnancies.
📅
Weekly Tracking
Expected gain by current pregnancy week.
⚠️
Disclaimer
Directs to healthcare provider.

How to Use

  1. Enter your pre-pregnancy weight and height.
  2. Select single baby or twins.
  3. Enter your current week of pregnancy.
  4. Click Calculate.

Frequently Asked Questions

Why does the recommended gain vary by BMI?▾
Women with lower pre-pregnancy weight need to gain more to support fetal development, while those with higher BMI have more stored energy reserves. The IOM 2009 guidelines account for this.
What if I am outside the recommended range?▾
This calculator provides general guidelines. Individual circumstances vary — always discuss weight gain targets with your midwife or obstetrician.
What are the IOM 2009 guidelines?▾
For singleton: Underweight (BMI<18.5): 12.5–18kg. Normal: 11.5–16kg. Overweight: 7–11.5kg. Obese: 5–9kg.