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Pregnancy Due Date Calculator

Your estimated due date, trimester, and how far along — in seconds.

  • No upload
  • Browser-based
  • Free
  • No signup
Estimated due date
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  • How far along today—
  • Trimester—
  • Estimated conception—
  • Days until due date—

This is an estimate for information only, not medical advice — your care provider dates your pregnancy precisely. Runs entirely in your browser; no dates are uploaded or stored.

Generated entirely in your browser.

How to use Due Date Calculator

  1. Choose how you want to calculate: first day of your last period, conception date, or IVF transfer date.
  2. Pick the relevant date on the calendar.
  3. For the last-period method, set your average cycle length (default 28 days).
  4. Read your estimated due date, how far along you are today, and your current trimester instantly.

Common use cases

  • Early pregnancy planning.
  • Tracking how far along you are.
  • IVF and conception dating.

Tips

  • If you had an early dating ultrasound, trust the date your provider gave you over any calculator estimate.
  • The due date is a 40-week midpoint — a full-term birth is anywhere from 37 to 42 weeks.
  • Cycle length only affects the last-period method; conception and IVF methods date from ovulation directly.

Troubleshooting

Frequently asked questions

How is my due date calculated?
By default we use Naegele’s rule: 280 days (40 weeks) from the first day of your last menstrual period, adjusted for your average cycle length. You can also calculate from a known conception/ovulation date (266 days) or an IVF transfer date based on the embryo’s age.
How accurate is the estimated due date?
It’s a well-established estimate, but only about 1 in 20 babies arrive on the exact due date — most are born within two weeks either side. An early ultrasound and your care provider give the most accurate dating.
What if my cycle isn’t 28 days?
Enter your average cycle length. Ovulation typically happens about 14 days before your next period, so a longer or shorter cycle shifts the due date accordingly. The tool applies this adjustment automatically for the last-period method.
Does this upload or store my information?
No. Everything is calculated locally in your browser with plain date math. No dates are uploaded, saved, or shared — nothing leaves your device.