About the Pregnancy Week Calculator
How many weeks and days pregnant you are today, your trimester and the weeks remaining.
Also known as: how many weeks pregnant, gestational age calculator, pregnancy month calculator, trimester calculator, gestational-age, pregnancy-month.
How to use this calculator
- Enter first day of last period, date to check.
- The result updates instantly as you type — press Calculate (or Enter) at any time.
- Review the breakdown shown under the main result.
- Use Copy result or Share to save the answer or send a link with your inputs.
Formula
Gestational age = days since LMP ÷ 7
Worked example
Using the values pre-filled in the calculator above:
- First day of last period: 2026-06-16
- Date to check: 2026-09-22
the calculator returns:
- Gestational age: 14 weeks 0 days
- Trimester: Second trimester
- Month of pregnancy: 4
- Weeks remaining: 26