Early pregnancy planning · Free planning tool

Pregnancy due-date estimator

Estimate a due date if you know the first day of your last period and have regular cycles. A date is an estimate, not confirmation of pregnancy.

An educational planning aid, not a diagnosis or treatment recommendation.

Your dates, a clearer picture

Use the first day of proper bleeding, not spotting.
Regular cycles only, between 21 and 35 days. See the limitations below before using your result.

Your entries are calculated in this page and are not submitted to ProFertility or saved to your patient record by this tool. Clear the form when using a shared device. These tools provide educational estimates, not medical advice.

How this is calculated

The estimate adds 280 days to the first day of the last period, then adjusts by usual cycle length minus 28 days. This assumes ovulation timing follows your usual cycle pattern. Your maternity team may update the date after a dating scan.

Before you rely on the result

This period-based method is not suitable for IVF or embryo-transfer dating, irregular cycles, uncertain bleeding dates or a recent pregnancy. Use your clinic’s date for treatment pregnancies. A dating scan is more accurate; a calculator cannot confirm pregnancy location or wellbeing.

Sources & further reading

Prepared by ProFertility · Updated 23 October 2026. Questions about your own circumstances? Contact our team.