Pregnancy Weight Gain Calculator

Track healthy weight gain during pregnancy by BMI. Enter pre-pregnancy weight, height, and current week. Get recommended total and trimester weight gain. Based on IOM/ACOG guidelines. Informational only—consult a doctor.

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Published: October 23, 2025 | Updated: October 23, 2025 | Reviewed by: Medical/Fertility Editor

⚠️ Medical Disclaimer: This calculator provides estimates based on general guidelines. Individual needs vary. Always consult your doctor or midwife for personalized medical advice.

Pregnancy Information

Weeks 1-42

Preset Profiles

IOM/ACOG Weight Gain Guidelines

BMI CategoryBMI RangeTotal Weight Gain
Underweight< 18.512.7-18.1 kg (28-40 lbs)
Normal18.5-24.911.3-15.9 kg (25-35 lbs)
Overweight25.0-29.96.8-11.3 kg (15-25 lbs)
Obese≥ 30.05.0-9.1 kg (11-20 lbs)

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How it works

Recommended Gain = Based on Pre-pregnancy BMI. We use guidelines from the Institute of Medicine (IOM) and ACOG to determine the healthy weight gain range for your BMI. We then break it down by trimester.

First trimester typically involves minimal gain (1-2 kg), while 2nd and 3rd trimesters average about 0.4 kg per week.

Inputs explained

  • Pre-pregnancy Weight: Your weight before becoming pregnant
  • Height: Your height for BMI calculation
  • Current Week: How many weeks pregnant you are (1-42)
  • Current Weight: Your weight right now

Example

Scenario: Normal Weight, Week 20

  • Pre-pregnancy: 60 kg, Height: 165 cm
  • BMI: 22.0 (Normal Weight)
  • Current Week: 20, Current Weight: 65 kg
  • Current Gain: 5 kg
  • Recommended Total: 11.3-15.9 kg
  • Expected at Week 20: ~5 kg
  • Status: On Track

Tips & notes

  • Weight gain is a normal and healthy part of pregnancy
  • Focus on a balanced diet with plenty of nutrients
  • Regular, moderate exercise is beneficial
  • Every pregnancy is different - these are general guidelines
  • Consult your doctor or midwife for personalized advice

FAQs

It depends on your pre-pregnancy BMI. A common range is 11-15 kg (25-35 lbs) for normal weight women.

BMI is calculated using your pre-pregnancy weight and height using the formula: weight (kg) / height (m)².

Very little, typically 1-2 kg (2-4 lbs) total during the first 12 weeks.

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Disclaimer

Informational tool based on IOM/ACOG guidelines. Individual needs may vary. Consult a doctor or midwife for personalized medical advice and monitoring throughout your pregnancy.

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