Read more: FAQs & context
Limits of the model
Ovulation timing, implantation delay, and ultrasound rounding all shift the true biological window. Never use this output for legal paternity timing or medical decisions.
Conception estimate
Work backwards from your estimated due date to an approximate conception window.
Purpose, how to use it, and benefits — the interactive tool is in the card above whenever you want to jump back.
From an estimated due date, it subtracts 266 days to suggest a single calendar date that represents a rough conception midpoint. It is a curiosity and planning aid, not proof of conception date.
Enter the EDD your provider gave you (often based on ultrasound), then tap Estimate conception. Read the short explanation of the 266-day model shown with your result.
Some families want to remember a symbolic conception season, plan pregnancy announcements, or compare with ovulation apps.
Ovulation timing, implantation delay, and ultrasound rounding all shift the true biological window. Never use this output for legal paternity timing or medical decisions.