Due date
Estimate delivery date from the first day of your last menstrual period.
Purpose, how to use it, and benefits — the interactive tool is in the card above whenever you want to jump back.
It estimates your baby’s estimated due date (EDD) from the first day of your last normal menstrual period (LMP). Most hospitals still use the “add 280 days” convention for initial dating before ultrasound adjusts it.
Select the first day of bleeding of your last period—not the last day of bleeding. Press Calculate due date to see the EDD in words and numbers. You can copy the summary for your pregnancy diary or to share with family.
Knowing your approximate due date helps you plan maternity leave, book time off, schedule scans, and understand how many weeks pregnant you are when you read apps or leaflets.
If your first-trimester ultrasound dates the pregnancy differently from LMP by more than a few days, your official EDD is often updated to match ultrasound. Always use the EDD printed on your hospital letter for medical decisions.
If your cycle is very long or short, LMP-based dating is less reliable. Mention cycle length at booking so your team can plan an early scan.