Pregnancy Weight Gain Calculator
Calculate pregnancy weight gain with our free online calculator
For progress tracking
Week 1-42 for progress tracking
Enter your pre-pregnancy details to see recommended weight gain ranges.
IOM Guidelines
- Based on pre-pregnancy BMI category
- Accounts for maternal and fetal health
- Reduces risk of complications
- Updated in 2009 by Institute of Medicine
Example Calculation
Pre-pregnancy: 130 lbs, 5'5" (BMI 21.6)
Category: Normal weight
Total gain:25-35 lbs (11.5-16 kg)
1st trimester:1-4 lbs
2nd/3rd:~1 lb/week
Important Factors
- Individual variation is normal
- Quality of nutrition matters most
- Regular prenatal care is essential
- Multiple pregnancies need different guidelines
Health Benefits
- Reduces risk of gestational diabetes
- Lowers chance of preterm birth
- Supports healthy fetal development
- Easier postpartum weight loss
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How to Use This Calculator
Step-by-step guide to get accurate results
What is a Pregnancy Weight Gain Calculator?
Our Pregnancy Weight Gain Calculator is a free tool designed to help expectant mothers estimate their ideal weight gain during pregnancy. It uses guidelines from the World Health Organization (WHO), Institute of Medicine (IOM), and NHS. <br><br>⚠️ Disclaimer: This tool is for educational purposes only. Always consult your doctor, gynecologist, or midwife for personalized guidance.
Why Pregnancy Weight Gain Matters
Supports Fetal Growth
Ensures healthy development of the baby.
Reduces Complications
Helps lower risks of gestational diabetes and high blood pressure.
Maintains Maternal Health
Supports the mother’s health and recovery after delivery.
Recommended Weight Gain During Pregnancy (IOM/WHO/NHS)
Underweight (BMI < 18.5)
28–40 lbs (12.5–18 kg)
Normal Weight (BMI 18.5–24.9)
25–35 lbs (11.5–16 kg)
Overweight (BMI 25–29.9)
15–25 lbs (7–11.5 kg)
Obese (BMI ≥ 30)
11–20 lbs (5–9 kg)
Twin/Multiple Pregnancy
Higher ranges recommended — consult your doctor.
How to Use the Pregnancy Weight Gain Calculator (Step-by-Step)
Step 1
Enter your height and weight (kg/cm or lbs/inches).
Step 2
Select your pre-pregnancy BMI category (or let the calculator auto-compute).
Step 3
Input your current week of pregnancy (1–40 weeks).
Step 4
Click Calculate → Instantly see your recommended weight gain range and chart.
Step 5
View trimester-specific guidance and weekly tracking.
Key Features of Our Tool
Global + Local Support
Works in kg/cm (Asia, EU) and lbs/inches (US, UK).
Trimester Tracking
Provides week-by-week pregnancy weight gain insights.
Guideline-Based
Follows WHO, IOM, and NHS recommendations.
Supports All BMIs
Works for underweight, normal, overweight, and obese mothers.
Multiple Pregnancies
Includes guidance for twin/multiple pregnancies.