Pregnancy BMI Calculator — Calculate Your Body Mass Index During Pregnancy

Pregnancy BMI Calculator

Calculate your Body Mass Index during pregnancy with our specialized calculator. Get personalized recommendations for healthy weight gain based on your pre-pregnancy BMI and current pregnancy week.

Step 1: Personal Information

Why Pre-Pregnancy Weight Matters

Your pre-pregnancy BMI determines the recommended weight gain range during pregnancy. This helps ensure optimal health for both mother and baby.

Step 2: Pregnancy Details

20 weeks

About Pregnancy Weight Gain

Healthy weight gain during pregnancy varies based on your pre-pregnancy BMI. The Institute of Medicine provides specific guidelines for different BMI categories.

Pregnancy BMI Results

Summary
Recommendations
Breakdown

Your Pregnancy BMI

24.9
Normal Weight
Pre-Pregnancy BMI
23.9
Current Weight Gain
3.0 kg
Recommended Gain
11.5-16.0 kg
Week of Pregnancy
20 weeks

Personalized Recommendations

Based on your Normal Weight BMI category:

For a singleton pregnancy, the recommended total weight gain is 11.5-16.0 kg (25-35 lbs).

Weekly Weight Gain (Second & Third Trimester):

0.4-0.5 kg (0.8-1.0 lb) per week

Nutritional Recommendations:

  • Increase calorie intake by approximately 340-450 calories per day in the second and third trimesters
  • Focus on nutrient-dense foods: fruits, vegetables, whole grains, lean proteins
  • Ensure adequate intake of folic acid, iron, calcium, and vitamin D
  • Stay hydrated with at least 8-10 glasses of water daily

Exercise Guidelines:

  • 30 minutes of moderate exercise most days of the week
  • Safe activities: walking, swimming, prenatal yoga, stationary cycling
  • Consult your healthcare provider before starting any new exercise regimen

BMI Categories & Weight Gain Guidelines

BMI Category BMI Range Recommended Total Gain (Singleton) Rate of Gain (2nd & 3rd Trimester)
Underweight < 18.5 12.5-18.0 kg 0.5-0.6 kg/week
Normal Weight 18.5-24.9 11.5-16.0 kg 0.4-0.5 kg/week
Overweight 25.0-29.9 7.0-11.5 kg 0.2-0.3 kg/week
Obese ≥ 30.0 5.0-9.0 kg 0.2-0.3 kg/week

BMI Calculation Formula

BMI = Weight (kg) / [Height (m)]²

To calculate BMI: Divide your weight in kilograms by your height in meters squared. For pregnancy BMI, we use pre-pregnancy weight to determine your category.

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