Health & Fitness
Pregnancy Due Date Calculator
Estimate your pregnancy due date and key milestones from your last period.
Free foreverRuns in your browserNo sign-up
Enter the first day of your last period to estimate the due date.
This tool is for general information only and is not medical advice. Talk to a qualified healthcare professional before making health decisions.
About the Pregnancy Due Date Calculator
This calculator estimates your pregnancy due date using Naegele's rule, based on the first day of your last menstrual period and your average cycle length.
Along with the estimated due date it shows your approximate conception date and when the second and third trimesters begin, so you can follow your pregnancy at a glance.
These are estimates; only a healthcare provider can confirm dates with a scan. Everything is calculated in your browser.
Key features
- Due date from last period
- Estimated conception date
- Trimester milestone dates
- Adjusts for cycle length
How to use
- 1Enter the first day of your last period.
- 2Adjust the average cycle length if needed.
- 3Read your estimated due date and milestones.
Frequently asked questions
- How is the due date calculated?
- It adds 280 days (40 weeks) to the first day of your last period, adjusted for your cycle length. This is the standard Naegele's rule.
- How accurate is it?
- Only about 1 in 20 babies arrive exactly on the estimated date. An early ultrasound gives a more precise estimate.