Pregnancy Due Date Calculator

Estimate your baby's due date and conception date from the first day of your last menstrual period (LMP), using the standard Naegele's rule of 280 days from LMP.

First day of last period (LMP)

Estimated due date

June 6, 2027

Conception estimateSeptember 13, 2026

Progress today0 weeks, 0 days

TrimesterFirst trimester

How it works

Naegele's rule adds 280 days (40 weeks) to the first day of your last period. Conception is estimated at around 14 days after LMP.

Due date = LMP + 280 days

Worked examples

Example
If your LMP was 1 January 2024, the estimated due date is around 7 October 2024.

Frequently asked questions

How accurate is the due date?

Only about 4–5% of babies are born exactly on the due date; it is an estimate.

How is pregnancy counted?

Pregnancy is dated from the first day of your last period, about two weeks before conception.

How many weeks is a full-term pregnancy?

A full-term pregnancy is about 40 weeks (280 days) from the last period.

This tool is for general information only and is not medical advice. Always consult a qualified healthcare professional before making health-related decisions.