Estimate an expected pregnancy due date from the last menstrual period and average cycle length. Use clinical dating for medical care.
Estimate an expected due date from the first day of the last menstrual period and an optional average cycle length. Pregnancy Calculator uses an LMP-based calendar estimate. Pregnancy dating can differ when cycle length varies or when clinical dating methods provide different information, so the result should be treated as an estimate. How to use Pregnancy Calculator: Enter the first day of the last menstrual period. Enter the usual cycle length if it differs from 28 days. Review the estimated due date and confirm important dates with a clinician. Common uses: Pregnancy date planning Preparing questions for prenatal visits General calendar estimation Is the due date exact? No. It is an estimate based on the supplied dates and assumptions. Can cycle length change the estimate? Yes. The calculator adjusts the simple LMP model for the entered average cycle length. When should I confirm the date? Use the dating method recommended by your pregnancy-care professional.