Pregnancy Weight Gain Calculator
Calculate recommended weight gain during pregnancy.
Pregnancy Information
Weight Gain Recommendations
Enter your information to calculate weight gain
About This Calculator
The Pregnancy Weight Gain Calculator helps you determine recommended weight gain during pregnancy based on your pre-pregnancy BMI and current week of pregnancy. Appropriate weight gain supports healthy fetal development and maternal health.
Weight gain recommendations vary based on pre-pregnancy BMI. The Institute of Medicine (IOM) guidelines provide evidence-based recommendations. Most weight gain occurs in the second and third trimesters, with minimal gain in the first trimester.
Formula & Calculation Method
Pregnancy Weight Gain Calculation:
IOM Guidelines (Total Gain):
Underweight (BMI <18.5): 12.5-18 kg
Normal (BMI 18.5-24.9): 11.5-16 kg
Overweight (BMI 25-29.9): 7-11.5 kg
Obese (BMI ≥30): 5-9 kg
Gain Pattern:
First Trimester (Weeks 1-13): 0.5-2 kg total
Second/Third Trimester: Steady weekly gain
Weekly Rate: 0.22-0.51 kg/week (varies by BMI)
Weight gain is typically minimal in the first trimester (0.5-2 kg), with most gain occurring in the second and third trimesters. The rate of gain is higher for underweight women and lower for overweight/obese women. These are general guidelines - individual needs may vary.
How to Use This Calculator
- Enter Pre-Pregnancy Weight or BMI: Input your weight before pregnancy or your pre-pregnancy BMI.
- Enter Current Week: Input your current week of pregnancy (1-42).
- View Results: See recommended weight gain for current week, total recommended gain, and gain rate.
Frequently Asked Questions
How much weight should I gain during pregnancy?
Weight gain recommendations depend on your pre-pregnancy BMI: Underweight (12.5-18 kg), Normal (11.5-16 kg), Overweight (7-11.5 kg), Obese (5-9 kg). These are IOM guidelines - your healthcare provider can provide personalized recommendations.
When do I gain the most weight?
Most weight gain occurs in the second and third trimesters. First trimester gain is typically minimal (0.5-2 kg), often due to morning sickness. Steady weekly gain begins around week 13.
What if I gain too much or too little?
If you're concerned about weight gain, discuss with your healthcare provider. They can help assess whether your gain is appropriate and provide guidance. Rapid or excessive gain may indicate issues that need attention.
What makes up pregnancy weight gain?
Pregnancy weight includes: baby (3-4 kg), placenta (0.5-1 kg), amniotic fluid (1 kg), increased blood volume (1.5-2 kg), increased fluid (1-2 kg), breast tissue (0.5-1 kg), and fat stores (2-5 kg).
Calculator by
NumCalculators Editorial Team
Multi-disciplinary Expert Team