Pregnancy due date calculator

Free Tool · Yogacruz

Pregnancy Due Date Calculator

Calculate your estimated due date using four different dating methods — last period, conception date, IVF transfer date, or ultrasound dating — the same approaches used in clinical practice, each with a note on how accurate it typically is.

This tool gives an educational estimate, not medical advice. Only about 5% of babies are born on their exact due date. Ultrasound dating from your provider, especially from a first-trimester scan, is the most accurate method — always confirm your dates with your doctor or midwife.

First day of last period

Average cycle length (days)

Frequently Asked Questions

Which due date method is most accurate?

A first-trimester ultrasound (before about 14 weeks) is considered the most accurate dating method, typically accurate to within 3-5 days. Last-period dating is less precise since it assumes a textbook 28-day cycle with ovulation on day 14, which varies between people.

How is the due date calculated from IVF transfer date?

For a day-5 (blastocyst) transfer, 261 days are added to the transfer date. For a day-3 transfer, 263 days are added. This accounts for the embryo's known age at the time of transfer, making IVF dating one of the most precise methods available.

Why do so few babies arrive exactly on their due date?

A due date is a statistical estimate of a 40-week average, not a prediction. Full-term birth is considered normal anywhere from 37 to 42 weeks, so a wide range of arrival dates is completely expected.