Due Date Calculator
Estimate your pregnancy due date and how far along you are.
Estimate your baby's due date and see how far along you are. Calculate from the first day of your last period (with an adjustable cycle length), your conception date, or an IVF transfer — and get your estimated due date, current gestational age in weeks and days, trimester, and conception date. Everything is worked out in your browser.
This is an estimate for general information, not medical advice. Your healthcare provider may adjust your due date.
Runs entirely in your browser — nothing is uploaded.
How to use the due date calculator
- 1Choose your method — last period, conception date, or IVF transfer.
- 2Enter the relevant date (and your cycle length if using last period).
- 3See your estimated due date, how far along you are, and your trimester.
Frequently asked questions
How is the due date calculated?
The classic method (Naegele's rule) adds 280 days — 40 weeks — to the first day of your last menstrual period, adjusted for your cycle length. Conception and IVF methods count forward from those dates instead.
How accurate is it?
It's a standard estimate; only about 1 in 20 babies arrive exactly on the due date. Your doctor may adjust the date after an ultrasound.
What if my cycle isn't 28 days?
Enter your average cycle length and the calculation adjusts the due date accordingly, since ovulation timing shifts with cycle length.
Is my information private?
Yes — everything is calculated locally in your browser and nothing is stored or uploaded.