Conception Date Calculator
NEWFind out exactly when you got pregnant. Back-calculate your conception date using either your expected due date or your last period.
How to use
- 1Format: method,YYYY-MM-DD
- 2Methods: dueDate or lastPeriod
- 3Examples:
- 4 - If you know your due date (EDD): dueDate,2024-12-25
- 5 - If you know your last period (LMP): lastPeriod,2024-03-20
Frequently Asked Questions — Conception Date Calculator
How is the conception date calculated?+
Conception date is typically calculated as occurring two weeks after the first day of your last menstrual period (LMP). If you enter a due date, we subtract 266 days (38 weeks) from it to find the date of conception based on Naegele's rule.
Is conception date the same as gestational age?+
No. Gestational age is counted from the first day of your last period, meaning you are technically "two weeks pregnant" on the day conception actually happens.
Can the conception date be wrong?+
Yes. Unless calculated via IVF transfer dates, a conception calculator provides an estimate. Sperm can live in the body for up to 5 days, and ovulation times vary, so actual conception often falls within a 3-5 day window of the estimate.