Baby Due Date Calculator

Pregnancy brings a calendar full of dates and milestones — due date, trimester boundaries, and the weeks between scans. This Baby Due Date Calculator computes one of those key dates from the information you have, so you can plan appointments and preparations.

The due date is most commonly estimated as 40 weeks from the first day of the last menstrual period (LMP) — the standard Naegele's rule used by obstetricians. If you know your conception date or current week instead, the tool works from what you have.

Only about 5% of babies arrive exactly on the due date; it is an estimate around week 40 that your doctor refines with ultrasound measurements. Treat the result as the planning date, not a promise.

Use the result to schedule the key scans — the first-trimester dating scan, the anomaly scan around 18–22 weeks, and the glucose test in the third trimester — and to plan maternity leave and the nursery.