Pregnancy Due Date Calculator
Estimate your due date from the first day of your last period, your conception date or an IVF transfer date — and see how many weeks pregnant you are, your trimester and key milestones.
This tool runs entirely in your browser.
How to use the Pregnancy Due Date Calculator
- 1Choose what you know: last period, conception date or IVF transfer.
- 2Enter the date (and your usual cycle length for the last-period method).
- 3Read your estimated due date, weeks pregnant and milestones.
What is the Pregnancy Due Date Calculator?
Pregnancy is dated from the first day of the last menstrual period (LMP), about two weeks before conception. Naegele’s rule adds 280 days (40 weeks) to the LMP, adjusted for cycles longer or shorter than 28 days.
From a known conception date, the due date is 266 days later; for IVF, 263 days after a 3-day embryo transfer or 261 days after a 5-day transfer.
Frequently asked questions
How accurate is a due date?
It is an estimate — most babies arrive within two weeks either side. An early ultrasound is the most accurate way to date a pregnancy.
Is the Pregnancy Due Date Calculator free and private?
Yes. The Pregnancy Due Date Calculator is free, needs no account, and runs entirely in your browser. What you type is never sent to a server or stored.
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