Pregnancy Due Date Calculator
Choose the method that fits what you know — your last period, your conception date, or an ultrasound scan — and get your estimated due date, how far along you are today, your trimester, and the key dates of your pregnancy.
28 days is average. Longer or shorter cycles shift your due date.
👆 Enter your date above and your estimated due date will appear here instantly — no sign-up, nothing leaves your browser.
Three ways to estimate your due date
Last period (Naegele's rule). The method doctors have used for over 200 years. Pregnancy is counted from the first day of your last menstrual period and lasts 280 days on average. It works best if you have a regular 28-day cycle — this calculator adjusts automatically if yours is longer or shorter.
Conception date. A pregnancy lasts about 266 days (38 weeks) from conception. If you tracked ovulation, used ovulation tests, or conceived through IVF, this method can be more precise than going by your period.
Ultrasound. Enter the date of a scan and how far along you were measured to be. The calculator works backwards to the equivalent last-period date and forwards to your due date. First-trimester scans are the gold standard for dating.
Reading your results
How far along is your gestational age today, in weeks and days. Trimesters divide pregnancy into three stages: the first runs to 13 weeks 6 days, the second from 14 to 27 weeks 6 days, and the third from 28 weeks until birth. The milestone timeline shows the dates of typical appointments and turning points — the anatomy scan, glucose screening, and the early- and full-term thresholds — so you can plan ahead.
Remember that a due date is the centre of a window, not an appointment. A healthy pregnancy can end any time from 37 to 42 weeks.
Getting ready for your baby
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