Pregnancy Due Date
Due date, current week and trimester milestones.
About Pregnancy Due Date
Pregnancy Due Date estimates the due date using Naegele’s rule — 280 days from the first day of the last period — adjusted if your cycle is not 28 days, which most calculators ignore. It also shows the current week, trimester and the key milestone dates. This is arithmetic, not medical advice.
How to use it
- Choose whether you know the last period date or the conception date.
- Enter it, and adjust the cycle length if yours is not 28 days.
- Read the due date, current week and trimester milestones.
Questions
How accurate is a due date?
Only about 4% of babies arrive on it. Roughly 80% arrive within two weeks either side. A dating ultrasound in the first trimester is considerably more accurate than any calculation.
Why is it counted from the last period rather than conception?
Because the last period is a date people know, while conception usually is not. It means the first two weeks of "pregnancy" happen before conception, which is why the count seems two weeks ahead.
Why does cycle length matter?
A longer cycle means later ovulation, so conception happened later than the standard assumption and the due date shifts accordingly. Most calculators skip this.
Pregnancy Due Date is free and runs entirely in your browser. No account, no upload, no watermark, no limit on use.