When did it actually happen? Enter a due date or a birthday and get the estimated conception date and window — math done in your browser, nothing sent anywhere. No signup, no fluff.
From a due date
Pregnancies are dated from the last period (40 weeks), but conception happens about 14 days in — this backs out the moment that counted.
–estimated conception date
The window is wider than the day
Sperm survive up to five days, the egg about one — so conception could fall anywhere in a six-day window around this date. An early ultrasound is what dates a pregnancy for real.
The eternal question — when was I (or they) conceived? Birthdays land anywhere from 37 to 42 weeks after conception, so this is the center of a spread, not a verdict.
–estimated conception date
Curious about more than dates?
A conception date tells you when — a DNA test tells you the family story around it.
These are estimates from standard obstetric math (conception ~266 days before a due date, ~266 days before a birthday), not a diagnosis. Early ultrasounds, irregular cycles, IVF dating, and babies arriving early or late all shift the real date — only a medical provider can date a pregnancy properly. Not medical advice.