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Pregnancy Due-Date Estimate

Estimate a conventional due date from the first day of the last menstrual period.

Educational estimate only. This does not diagnose pregnancy, provide medical advice, or replace care from a doctor or qualified healthcare professional.

Your inputs

Your result

Enter your information and select Calculate to see the result.

How this calculator works

The estimate adds 280 days, following the ACOG convention for a 28-day cycle with ovulation near day 14.

Change one assumption at a time to see which inputs have the greatest effect on the estimate.

Worked example

A clinician may compare menstrual dating with an early ultrasound.

Limitations

Cycles and ovulation vary, recall may be inaccurate, and clinicians may revise dating using ultrasound or assisted-reproduction information. This is not medical advice.

Review this educational estimate against current quotes, official information, and your own budget before making a financial decision.