How we worked it out
Updated as you change the numbers.
- Last period = due date − 280 days.
- Ovulation and conception are about 14 days after the period starts.
Method and assumptions
The due date is 280 days after the last period, and ovulation is typically about 14 days after it starts, so conception is about 266 days before the due date. Cycles vary, so the real date can be a few days either side.
Questions
When did I conceive if my due date is February 5, 2027?
Most likely around May 15, 2026.
Sources
Method and figures checked on . Every worked answer on this page is covered by an automated test. Found a mistake? Tell us.