Pregnancy Due Date Calculator

Enter the first day of your last period to estimate your due date, how many weeks along you are, your trimester and days remaining. A quick guide — your doctor’s scan is more precise.

How to use

1. Enter the first day of your last menstrual period.
2. Adjust your average cycle length if needed.
3. Read your estimated due date and progress.

Frequently asked questions

How is the due date estimated?

Using Naegele’s rule: roughly 280 days (40 weeks) from the first day of your last period, adjusted for your cycle length.

How accurate is it?

It is an estimate. An ultrasound dating scan from your doctor is more accurate, especially with irregular cycles.

Related tools