Estimate your pregnancy due date, gestational age, and key timelines using LMP, ultrasound scans, IVF transfer dates, or conception dates.
How it Works & Formula
Uses Naegele's Rule to estimate the date of delivery for pregnant mothers.
Practical Examples
LMP of Jan 15th + 7 days = Jan 22nd, minus 3 months = October 22nd due date.
Frequently Asked Questions
How is an estimated due date calculated from the last menstrual period (LMP)?
Estimated due date is typically calculated as 280 days or 40 weeks from the first day of the last menstrual period. If cycle length differs from 28 days, adjusting by cycle length may improve the estimate.
How does ultrasound dating estimate a due date?
Ultrasound dating uses gestational age measured on the ultrasound examination date (CR-length or biparietal diameter) and then back-calculates the estimated due date by adding the remaining days of a 280-day cycle.
How is due date calculated for an IVF pregnancy?
For IVF pregnancy, the due date is calculated from the embryo transfer date and embryo age at transfer. Conception is estimated as the transfer date minus embryo age, and the estimated due date is conception plus 266 days.
What is Naegele’s Rule?
Naegele’s Rule is a standard way of calculating the due date. It adds one year, subtracts three months, and adds seven days to the first day of the last menstrual period (LMP).