👶

Due Date Calculator

Find out your estimated due date based on your last menstrual period or conception date. Plan for your baby’s arrival with trimester-by-trimester information.

This tool is informational and does not replace medical advice. Always consult your baby's pediatrician.

How does this calculation work?

The due date calculator uses Naegele’s Rule, the classic method adopted worldwide by obstetricians. From the date of your last menstrual period (LMP), it adds 280 days (40 weeks) to estimate the birth date. If you enter your conception date, the calculation starts from that point with 266 days (38 weeks). The tool also shows which trimester you are in, how many weeks remain, and important milestones of the pregnancy. Keep in mind: only about 5% of babies are born on the exact due date. Most arrive within a two-week window before or after the EDD. Regular medical follow-up is essential.

Frequently asked questions

Is the due date exact?▾
No. The EDD is an estimate. Studies show that only about 5% of babies are born on the calculated date. Most full-term deliveries occur between 37 and 42 weeks of gestation. The due date serves as a reference for prenatal care and to help plan logistics for the baby’s arrival.
How is the due date calculated using Naegele’s Rule?▾
Naegele’s Rule works like this: take the first day of your last menstrual period, subtract 3 months, and add 7 days (plus 1 year if necessary). This is equivalent to adding 280 days to the LMP. For example, if your LMP was January 1st, the EDD would be October 8th. This method assumes regular 28-day cycles.

Organize your baby's routine with UpMom

Routines, vaccines, sleep, schedule and more, all in one app made for moms.

Download free on App Store
← See all tools