Birth Weight Calculator
Calculate estimated fetal weight during pregnancy. Track baby’s growth percentiles and monitor healthy development.
Step 1: Pregnancy Details
28 weeks
Growth Percentiles
Estimated fetal weight is compared to standard growth charts. 10th-90th percentile is considered normal range for gestational age.
Step 2: Health Factors
Average Birth Weights
Full term (40 weeks) average: 3.5 kg (7.7 lbs). Low birth weight: <2.5 kg (5.5 lbs). High birth weight: >4.0 kg (8.8 lbs).
Estimated Fetal Weight
Summary
Growth Percentiles
Development Timeline
Estimated Fetal Weight
1.2 kg
28 weeks gestation • 45th percentile
45%
Percentile
1.2 kg
Kilograms
2.6 lbs
Pounds
1200 g
Grams
Gestational Age
28 weeks
Growth Status
Normal
Expected at 40 weeks
3.4 kg
Days to Full Term
84 days
Growth Percentile Chart
| Percentile | Weight at 28w | Weight at 40w | Classification |
|---|
Pregnancy Development Timeline
Fetal Weight Calculation
Based on Hadlock Formula
Estimated fetal weight = (Gestational age in weeks × 30) + (Mother’s weight factor) ± (Health factors adjustment). This is an estimate only—actual ultrasound measurements provide more accurate results.
Consult Your Healthcare Provider
This calculator provides estimates only. Always consult your doctor or midwife for accurate fetal assessments and personalized medical advice during pregnancy.
Find a Healthcare Provider