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Fetal Length Calculator – Baby Size by Week

Calculate estimated fetal length by gestational age

This calculator provides estimates based on average growth. Actual measurements should be obtained through ultrasound by a healthcare professional.
Calculate Fetal Length

How to Use

  1. Enter the gestational age in weeks
  2. Enter additional days if applicable (0-6)
  3. Click calculate to see estimated fetal length
  4. Results show CRL for early pregnancy or CHL for later stages

What is Fetal Length?

Fetal length is a measurement used to assess baby's growth during pregnancy. Two main measurements are used: Crown-Rump Length (CRL) in early pregnancy and Crown-Heel Length (CHL) in later pregnancy.

Types of Measurements

  • Crown-Rump Length (CRL): Measured from top of head to bottom of torso, used in weeks 6-13
  • Crown-Heel Length (CHL): Measured from top of head to heel, used from week 14 onwards
  • CRL is most accurate for dating pregnancy in the first trimester
  • Later measurements may include biparietal diameter and femur length

Normal Growth Patterns

Fetal growth follows predictable patterns but individual variation is normal. Factors affecting size include genetics, maternal nutrition, and placental function.

Frequently Asked Questions

How accurate is the fetal length calculator?
This calculator provides average estimates. Actual measurements from ultrasound are more accurate and account for individual variation. Always consult your healthcare provider for precise measurements.
What's the difference between CRL and CHL?
Crown-Rump Length (CRL) measures from head to bottom and is used in early pregnancy (weeks 6-13). Crown-Heel Length (CHL) measures from head to heel and is used from week 14 onwards when the fetus is larger.
Is fetal size important?
Fetal size helps healthcare providers monitor baby's growth and development. Measurements that fall outside normal ranges may warrant additional monitoring, but many babies are healthy despite size variations.

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