Gestational Age Calculator
Find your current gestational age in weeks and days from the first day of your last menstrual period (LMP).
What is Gestational Age?
Gestational age is the standard clinical measure of how far along a pregnancy is. It is counted from the first day of the last menstrual period — about two weeks before conception. Gestational age (in weeks + days) is recorded at every prenatal visit and guides timing of screenings and tests.
How is it calculated?
Gestational age = (today − LMP) days, expressed as weeks + remaining days. Term pregnancy is 37–42 weeks.
Frequently Asked Questions
- Why count from LMP?
- It is universal, easy to remember and clinically standard.
- How is GA confirmed?
- First-trimester ultrasound is the most accurate.
- What if cycles are irregular?
- Ultrasound is preferred over LMP-based GA.