About DueDateCalculator.ai

DueDateCalculator.ai is a free, private suite of pregnancy-timing calculators. We help people estimate a due date, gestational age, trimester, and pregnancy week — clearly and calmly, with the math you can check.

What we do

Every calculator on this site — due date, conception date, pregnancy week, IVF, reverse due date, and gestational age — runs on a single, shared calculation engine. That engine uses standard obstetric dating: 280 days from the first day of the last period, 266 days from conception, and embryo-age-adjusted dating for IVF. The same engine is covered by a fixed set of golden test vectors, so the numbers stay consistent everywhere.

Accurate, not authoritative

These tools give estimates. An early ultrasound is the most accurate way to confirm dating, and your clinician sets the official due date used for your care. We say so on every page, because it matters.

Private by design

The dates you enter never leave your device. There are no accounts and nothing is stored or sent. You can read more on our privacy page.

Medical review

Our clinical content is written to follow guidance from the American College of Obstetricians and Gynecologists (ACOG) and is being prepared for review by a qualified OB-GYN. Until that review is complete and published, the site is educational information only — not medical advice.

Part of MyCycle

DueDateCalculator.ai is a MyCycle product. Questions or feedback? Get in touch.