Overview
What Is a Conception Date Calculator?
This tool estimates your likely conception date based on your due date or last menstrual period, working backward from standard pregnancy timing.
Estimate your conception date instantly.
This tool estimates your likely conception date based on your due date or last menstrual period, working backward from standard pregnancy timing.
Useful for general timeline understanding, though this is an estimate, not a precise medical determination.
Input either your due date or last menstrual period.
The result updates automatically.
Typically calculated as 266 days before your due date, or about 14 days after your last period began.
No, this is an estimate based on average timing - actual conception can occur within a range of days.
No, this is an informational estimate - your healthcare provider's methods (like ultrasound dating) are more precise.
Irregular cycles make this estimate less reliable - consult your healthcare provider for more personalized timing.
Not necessarily - sperm can survive for several days, so conception may occur up to a few days after intercourse.
No, calculations happen entirely in your browser.
This is essentially the reverse calculation - see our due date calculator for the forward version.
Some people want this for personal timeline curiosity or specific medical/legal questions.
For medical or legal purposes, always consult a healthcare provider rather than relying solely on this estimate.
Yes, completely free with no sign-up required.