What Is the Expected Date of Delivery?
The expected date of delivery (EDD), or due date, is the estimated day a baby will be born. It is set at 40 weeks, or 280 days, from the first day of the last menstrual period (LMP). Doctors use it to plan antenatal visits, tests and scans at the right stage of pregnancy.
How This Calculator Works
- Last menstrual period: adds 280 days to the first day of the last period, adjusted for the usual cycle length.
- Conception date: adds 266 days (38 weeks) to the date of conception, as in IVF or when the date is known.
- Ultrasound scan: counts back from the gestational age on the scan report to find the start of pregnancy, then adds 40 weeks.
The result shows the due date, how many weeks and days pregnant today, the trimester, key dates, and the usual window for common antenatal tests, scans and vaccines.
Important Note
This calculator gives an estimate for general information only. It is not medical advice. The due date, the tests needed and their timing should always be confirmed by the treating doctor, especially after an ultrasound scan.
For Gynecologists: Save It in the Patient's Record
Doctopath's gynecology case paper calculates the EDD and gestational age at every visit, records ANC findings, tracks the test and scan schedule, flags high-risk pregnancies and can send WhatsApp reminders for upcoming tests. Contact us for a demo set up for your clinic.
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Frequently Asked Questions
How is the pregnancy due date calculated?
The usual method is Naegele's rule: add 280 days (40 weeks) to the first day of the last menstrual period. This assumes a 28-day cycle, so the calculator moves the date later or earlier when the usual cycle is longer or shorter.
Which is more accurate, the LMP date or the ultrasound date?
An early ultrasound, especially in the first trimester, is generally considered more reliable than the LMP, particularly when periods are irregular or the LMP is not remembered. When the two differ, the doctor decides which date to follow.
How many weeks pregnant am I?
Pregnancy is counted from the first day of the last period, not from conception, so the calculator shows the weeks and days completed from that date until today.
Will the baby be born on the due date?
Usually not exactly. The due date is an estimate, and only a small share of babies are born on that day. A birth from 37 weeks onwards is considered full term.
Are the dates I enter saved or shared?
No. The calculation happens in your browser. The dates you enter are not saved and are not sent to Doctopath.
Can doctors use this for their patients?
Yes, for a quick estimate. Clinics that want the due date, gestational age and test schedule saved in each patient's record can use the pregnancy card in Doctopath's gynecology case paper.