How do you calculate a due date from conception?

Add 266 days to the estimated conception date. Pregnancy is 280 days from the last menstrual period, but conception typically happens about 14 days after that.

What if I'm not sure of the exact conception date?

Use our main due date calculator with the first day of your last period, or try the reverse due date calculator to work backwards from a known due date.

Is conception date the same as ovulation date?

Very close. Conception usually happens within 24 hours of ovulation, so most people use the ovulation date as the conception date for this calculation.

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Conception Date Calculator

Enter your estimated conception or ovulation date to calculate your due date.

Estimated conception date

Estimated due date

Wednesday, May 26, 2027

This is an estimate for information only — only about 1 in 20 babies arrive on their due date. Always confirm dates with your midwife or doctor.

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Due date calculator Reverse due date Ovulation calculator

Conception Date Calculator

Frequently asked questions

How do you calculate a due date from conception?

What if I'm not sure of the exact conception date?

Is conception date the same as ovulation date?