Due Date Calculator
Find out when your little one is likely to arrive, how far along you are, and the key dates to plan around — from your NHS scans to telling your employer.
Your details
Good to know: this is an estimate. Only around 1 in 20 babies arrive on their due date — most are born between 37 and 42 weeks. Your midwife will confirm your due date at your dating scan.
Enter your dates and we'll show your due date, how far along you are, and a timeline of key dates.
Get milestone reminders
We'll email you a short, friendly reminder before each key date — scans, vaccinations, maternity leave deadlines and more.
How your due date is calculated
Pregnancy is usually counted as 40 weeks (280 days) from the first day of your last period — not from conception. That's why you're considered around 2 weeks pregnant at the time you conceive.
If your cycle is longer or shorter than 28 days, ovulation usually happens later or earlier, so we adjust your due date by the difference. If you know your conception date, we add 266 days (38 weeks). For IVF, we count from your embryo transfer date, allowing for the age of the embryo.
Your dating scan
In the UK, you'll be offered a dating scan between 10 and 14 weeks. The sonographer measures your baby to give a more accurate due date, which may differ slightly from the one calculated here. Always go by the date your midwife gives you.
Your expected week of childbirth
For maternity and paternity leave, employers use your expected week of childbirth — the week (Sunday to Saturday) your due date falls in. Your deadline to tell your employer is the end of the 15th week before that week, and the earliest you can start maternity leave is 11 weeks before it. We've worked out both for you above.
This calculator is for general information only and isn't a substitute for advice from your midwife, GP or other healthcare professional. For more guidance visit nhs.uk/pregnancy. For leave and pay rules see gov.uk/maternity-pay-leave.