Pregnancy Due Date Calculator

How to use

1. 1Pick a calculation method: last period (LMP), conception date, or ultrasound dating.
2. 2Enter the matching date. For LMP, also enter your average cycle length (default 28 days). For ultrasound, enter the scan date and the gestational age weeks and days from the report.
3. 3Read the estimated due date, your current gestational age in weeks plus days, and the trimester progress bar.
4. 4Scan the milestones list for the calendar dates of trimester boundaries, full term, late term, and post term.
5. 5Use Copy summary to copy a text version of the estimate to share or save.

About this tool

Pregnancy Due Date Calculator estimates an estimated due date (EDD) and the calendar dates of the major pregnancy milestones from three common starting points: the first day of your last menstrual period (LMP), a known conception date, or a dated ultrasound scan. The LMP method uses Naegele's rule (LMP plus 280 days), with a small correction when your average cycle length is shorter or longer than 28 days. The conception method adds 266 days to the conception date, which is useful when ovulation, an IVF transfer, or a single intercourse event pinpoints when the pregnancy began. The ultrasound method takes the scan date and the gestational age reported on the scan (weeks plus days) and back-solves to give the same due date a clinician would record. Once the EDD is set, the tool shows the current gestational age in weeks and days, the trimester you are in, and a progress bar against the full 40-week timeline. The milestones list gives the calendar dates for the end of the first trimester (13w 0d), the end of the second trimester (26w 6d), the start of the third trimester (27w 0d), the start of full term (37w 0d), the estimated due date (40w 0d), the late-term window (41w 0d), and the post-term mark (42w 0d). Everything runs locally in your browser; the dates you enter never leave your device. This is a calendar estimate, not medical advice. Most pregnancies do not deliver on the calculated date, so talk to a qualified healthcare professional for personalized care and monitoring.

Free to use. Works in your browser. No signup, no login.