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Pregnancy Due Date Calculator

A free Pregnancy Due Date Calculator that estimates your due date using Naegele's rule — add 280 days to the first day of your last menstrual period (or 266 days to the conception date). See your current week of pregnancy, trimester, days to go, and important milestones like the end of each trimester. Adjust for your average cycle length for a more personalised estimate. Everything runs in your browser — private and mobile-friendly.

Your Details

How do you know the date?

28 days
21 days28 (standard)35 days

This estimate is informational — your healthcare provider will confirm your due date, typically with an early ultrasound.

Frequently Asked Questions

Everything you need to know about due dates and pregnancy milestones

How is the due date calculated?
Using Naegele's rule: add 280 days (40 weeks) to the first day of your last menstrual period. When the conception date is known instead, we add 266 days (38 weeks). Due dates are estimates — only about 5% of babies arrive exactly on their due date.
Why do you ask about my cycle length?
Naegele's rule assumes a 28-day cycle. If your cycle is longer or shorter, we adjust the estimate by the difference — for example, a 35-day cycle adds 7 days. This makes the estimate slightly more personalised.
When is a baby considered full-term?
A pregnancy is considered full-term between 39 and 40 weeks (early term is 37–38 weeks). Babies born between 37 and 42 weeks are generally considered normal. Your healthcare provider will confirm your due date with an early ultrasound.
Is my data private?
Yes. Everything runs in your browser. Your dates and cycle information never leave your device.

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