Gestational Age Calculator
Weeks pregnant from LMP.
Enter your values
Results update instantly as you type — no submit needed.
Results
- Gestational age
- 18 weeks 0 days
- Trimester
- Second
- Days remaining to 40 weeks
- 154
- Percent of pregnancy complete
- 45%
- Estimated fetal age
- 16 weeks
Quick answer
Gestational age counts from the first day of your last period, so it runs about two weeks ahead of conception.
How to use the Gestational Age Calculator
- 1Count days since the first day of your last period.
- 2Enter that number.
- 3Read your gestational age and trimester.
Frequently asked questions
Why is fetal age two weeks less?
Ovulation usually happens about 14 days after your period starts.
Is an ultrasound more accurate?
Yes, especially a first trimester dating scan.