What is the EDD?
EDD stands for estimated date of delivery — the date you reach 40 weeks of pregnancy, counted from the first day of your last menstrual period (LMP). You will see it on pregnancy notes, scan reports, appointment letters, insurance and employer forms, and in pregnancy apps. It is the same thing as your due date.
This calculator works out your EDD from your last period, conception date or IVF transfer, and then shows it in the formats different forms and systems use, so you don’t have to convert it by hand.
Abbreviations you may see
| Abbreviation | Meaning |
|---|---|
| EDD | Estimated date of delivery (due date) |
| EDC | Estimated date of confinement — older term for the same date |
| EDB | Estimated date of birth |
| LMP | Last menstrual period — the first day of it |
| GA | Gestational age, e.g. 20+3 = 20 weeks 3 days |
| EWC | Expected week of childbirth (used for UK maternity leave) |
Date formats around the world
The same day can be written in ways that look very different. February 19, 2027, for example, is 02/19/2027 in the US, 19/02/2027 in the UK and much of the world, and 2027-02-19 in the international ISO format. Mixing them up can put the wrong date on a form — 03/04 could mean March 4 or April 3. The calculator lists each format clearly labelled.
It also shows the day of the year and the ISO week number, which some workplace systems and planners use.
Keeping your EDD up to date
Your EDD may be revised after your first dating scan. If that happens, use the new date everywhere. If you have both an LMP-based date and a scan, the EDD Calculator Pregnancy shows which one clinicians usually keep, and the EDD Calculator Due Date compares the formulas used to calculate it.