Free due date calculator: use the Naegele method on your last menstrual period to estimate an expected delivery date. An approximate estimate only. 100% Local
How to Use the Due Date Calculator
Enter the first day of your last period and press Estimate Due Date. The result updates as you type.
How it works
The Naegele method adds 280 days (40 weeks) to the last menstrual period.
It assumes a regular 28-day cycle, so the date may shift for other cycles.
Your clinician may adjust the date after an ultrasound.
Features
Estimated delivery date
Naegele method (LMP plus 280 days)
Simple single date input
All processing runs locally in your browser. Your data is not uploaded to any server.
This is an approximate estimate, not medical advice.