Pregnancy Due Date
Estimate a due date from the first day of the last period, or from a conception date.
Estimated due date: Wednesday, April 21, 2027.
14 weeks and 4 days. Second trimester.
This is an estimate from a calendar rule. It is not a diagnosis, and an ultrasound can change the date.
How it works
ACOG Committee Opinion No. 700 says that, by convention, the estimated due date is 280 days after the first day of the last menstrual period. The rule assumes a 28-day cycle with ovulation on day 14. Counting from conception is therefore 266 days, which is 280 minus 14.
Gestational age is counted from the last period. From a conception date, 14 days are added so the week count uses that same convention. The first trimester runs through 13 weeks and 6 days, the second through 27 weeks and 6 days, and the third from 28 weeks.
A different cycle length is not used to move the date. Ultrasound measurements and IVF transfer dates are not estimated here.
FAQ
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An estimate from a published dating convention, not a diagnosis or medical advice. Ask a clinician before relying on it for care.