How to interpret this estimate

Estimate a due date using the conventional 280-day pregnancy calculation. Adds 280 days, or 40 weeks, to the first day of the last menstrual period.

When this result is useful

Use it to estimate a calendar due date from the first day of the last menstrual period before clinical confirmation.

Common limitations

Cycle length, conception timing, assisted reproduction, and ultrasound dating can change the clinical due date. A healthcare professional should confirm pregnancy dating.

This calculator uses the selected inputs and the fixed formula behind the tool to produce an estimate. Review the units, assumptions, and result labels before using the output for planning.

Health results are screening or planning estimates only. They do not diagnose health status or replace advice from doctors, dietitians, or qualified healthcare professionals.

Read the medical disclaimer for more context.