Do I need to sign up?

No. The tool works without an account.

Are my data uploaded?

Compatible operations run locally in the browser.

Using Naegele's rule: add 280 days (40 weeks) to the first day of the last menstrual period. This is an estimate, not a guarantee.

No. This is a simple mathematical estimate. Always consult a healthcare professional for pregnancy care.

You can enter a date 14 days after conception as the LMP equivalent, or use a more advanced calculator with your provider.

Tool guide

Practical information to understand the result and use this tool correctly.

Calculate pregnancy due date from last menstrual period using Naegele's rule (280 days).

The tool runs directly in the browser for immediate results.

Do I need to sign up?: No. The tool works without an account.
Are my data uploaded?: Compatible operations run locally in the browser.
How is the due date calculated?: Using Naegele's rule: add 280 days (40 weeks) to the first day of the last menstrual period. This is an estimate, not a guarantee.
Is this medical advice?: No. This is a simple mathematical estimate. Always consult a healthcare professional for pregnancy care.
What if I know the conception date?: You can enter a date 14 days after conception as the LMP equivalent, or use a more advanced calculator with your provider.