Enter the Crown-Rump Length and the constant 6.2 into the calculator to determine the gestational age in weeks.

Crl To Weeks Formula

The following formula is used to calculate the gestational age in weeks based on the Crown-Rump Length (Crl).

W = (Crl + 6.2) / 0.5

Variables:

  • W is the gestational age in weeks
  • Crl is the Crown-Rump Length in millimeters (mm)

To calculate the gestational age in weeks, add 6.2 to the Crown-Rump Length, then divide the result by 0.5. This formula is based on the average growth rate of a fetus in the first trimester.

What is a Crl To Weeks?

Crl To Weeks is a method used in pregnancy to estimate the gestational age of a fetus. Crl stands for Crown-Rump Length, which is the measurement from the top of the baby's head (crown) to its bottom (rump) when it is curled up in the womb. This measurement is taken during an ultrasound scan, and it is used to accurately determine how many weeks pregnant a woman is, especially in the first trimester.

How to Calculate Crl To Weeks?

The following steps outline how to calculate the Crl To Weeks using the formula: W = (Crl + 6.2) / 0.5


  1. First, determine the Crown-Rump Length (Crl) in millimeters (mm).
  2. Next, add 6.2 to the Crl value.
  3. Next, divide the sum by 0.5.
  4. Finally, calculate the gestational age in weeks (W).
  5. After inserting the Crl value and calculating the result, check your answer with the calculator above.

Example Problem:

Use the following variables as an example problem to test your knowledge.

Crown-Rump Length (Crl) = 40 mm