Pregnancy Due Date Calculator
Estimate your due date and current pregnancy week from your last period.
Your details
2045
How the pregnancy due date calculator works
Naegele's rule adds 280 days to the first day of the last menstrual period, adjusted if your cycle is not 28 days.
Formula
due date = LMP + 280 days (adjusted for cycle length)
Worked example
An LMP of 1 February with a 28-day cycle gives a due date around 8 November.
Frequently asked questions
How accurate is a due date?
Only about 4% of babies arrive exactly on it; most are born within two weeks either side.
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