Pregnancy due date calculator

Due date = first day of last period + 280 days (+ cycle length − 28 days), or conception date + 266 days. Pregnancy is counted from the first day of the last menstrual period, about two weeks before conception, so a full-term pregnancy is about 40 weeks. If your cycle is longer or shorter than 28 days, ovulation and the due date shift by the difference. A dating ultrasound scan gives a more accurate estimate.

With calculate from First day of last period, date 2026-07-24, average cycle length (days) 28, show progress as of 2026-10-16, the estimated due date is 30 April 2027. How far along (on the calculation date): 12 weeks 0 days; Trimester: First trimester; Days until the due date: 196 days; Conception (approximate): 7 August 2026.

An estimate only. Your midwife or doctor will confirm your due date. This is an estimate based on the inputs and assumptions shown on this page, not professional advice. Check anything with financial, health or safety consequences independently.

Yes. Calculations run in your browser and your numbers are not sent to a server. A share link contains the inputs you choose to share, so check it before sending it to anyone.

It is an estimate. Most babies are born within about two weeks either side of it, and a dating ultrasound scan gives a more accurate estimate than a calculation from the last period.

The first day of the last period is usually known, while the day of conception is not, so pregnancy length is counted from it by convention. Conception typically happens about two weeks later.