About the Pregnancy Calculator
See exactly how far along you are. Enter the first day of your last menstrual period (or your due date) to find your current week of pregnancy, trimester, days to go and dates for key milestones and scans.
How to use it
- Choose the date you know: last period, conception or due date.
- Enter the date (and cycle length if using your last period).
- Review your progress and milestone timeline.
Formula & method
Due date = LMP + 280 days + (cycle length − 28)
Gestational age = 280 − days until due dateFrequently asked questions
Why is pregnancy counted from the last period?
Doctors date pregnancy from the first day of the last menstrual period because it is usually known, even though conception happens about two weeks later.
Results are estimates for general information only and are not financial, tax, legal or medical advice. Please confirm important decisions with a qualified professional.