About this tool
Estimate the due date and current gestational age using Naegele's rule (LMP + 280 days). Gestational age is reported as completed weeks plus extra days.
Formula
EDD = LMP + 280 days. gestationalWeeks = floor((today − LMP) / 7).
Worked example
LMP 2026-01-01 → EDD ≈ 2026-10-08. As of 2026-05-05 → ~17 weeks 5 days.
Notes
LMP-based dates assume a 28-day cycle with ovulation on day 14. Ultrasound dating in early pregnancy is more accurate. Always confirm with a healthcare provider.