Pregnancy due date calculator
Find out when you will welcome your new baby into the world.
Leave it at 28 if your cycle is regular or you are not sure.
Nothing you enter leaves your browser.
Pick a date above and your dates, along with the week-by-week plan, appear here.
Questions about your due date
- How do I use the due date calculator?
- Pick how you want to work it out, from your last period or the day you conceived, then enter that date. We do the maths and show your due date.
- How is my due date calculated?
- We add 280 days to the first day of your last period. The weeks are counted from that same day, starting at week 0 and not week 1, up to week 40. If your cycle is longer or shorter than 28 days, we adjust for it. From the day you conceived, we add 266 days.
- Can my due date change?
- Yes. An early scan can move it. So can a cycle that turns out longer or shorter than you thought. The earlier the scan, the closer the date. Your doctor or nurse will change it if they need to.
- How likely am I to give birth on my due date?
- Not very. Only about five in every hundred babies come on the day itself. Think of it as a due week, or even a due month.
- When is the naming ceremony?
- The eighth day, counting the day of birth as day one. We work out the date for you, so you have something to give whoever is asking.
- When should I start buying things?
- The plan under your result puts each thing in the week you will want it, so you sort out the urgent ones early. To see the whole list at once, open the baby items checklist.