Pregnancy Due Date Calculator
Estimate a due date from the first day of your last menstrual period (LMP), a known conception date, or an IVF transfer date — plus the current gestational age and trimester.
Check your input
Please enter a valid date.Formula
LMP method: due date = first day of last period + 280 days (adjusted for cycle length)
Example
Input
LMP 1 January 2026, 28-day cycle
Result
Due 8 October 2026
Frequently asked questions
It is an estimate. Around 80% of babies are born within two weeks either side of it.
Enter your average cycle length and the estimate is adjusted accordingly.
A first-trimester ultrasound is the most accurate method of dating a pregnancy.
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