Enter the first day of your last period to estimate your due date, how far along you are, and your trimester — instantly.
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The standard method (Naegele’s rule) adds 280 days — 40 weeks — to the first day of your last menstrual period, adjusted slightly if your cycle isn’t 28 days. It estimates the date, but only about 1 in 20 babies actually arrives on it.
It gives a solid estimate from your last period, but a first-trimester dating ultrasound is more accurate — your provider may adjust the date. A normal, full-term birth can happen anytime from 37 to 42 weeks.
This tool uses your last period. If you know your conception date, your due date is roughly 266 days after it; IVF due dates are calculated from the transfer date. Ask your provider for an exact IVF due date.
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