What you provide
What you provide
- First day of the last menstrual period
- Usual cycle length when reasonably regular
- Date for the gestational-age view
PREGNANCY / LMP ESTIMATE
Pregnancy Due Date Calculator
Estimate a due date and gestational age from the first day of the last menstrual period, with cycle adjustment and ultrasound limitations shown clearly.
- 01 Calculated in this tab
- 02 Values stay in this browser tab
- 03 Use boundary
Use boundary
Calculation path
The conventional estimate adds 280 days to the LMP date for a 28-day cycle, then shifts by the difference between your usual cycle and 28 days.
Calculation path
Estimated due date = first day of LMP + 280 days + (usual cycle length - 28 days). Estimated gestational age counts from the LMP date.
What you receive
What you receive
- Estimated due date
- Estimated gestational age and stage
- Estimated conception date and days to or past the estimate
Use boundary
Choose the maximum decimal places shown. This does not increase source accuracy.
This page cannot confirm pregnancy or replace clinical dating. Early ultrasound and assisted-conception dates may establish a different due date.
Reviewed reference factors