Due Date Calculator: when is my baby due?
Enter the first day of your last period to estimate your due date, how far along you are and key milestones.
For general information only, not medical advice. Speak to your GP, midwife or a health professional about your own health.
How it works
Your estimated due date is 280 days (40 weeks) after the first day of your last menstrual period, adjusted for your cycle length (Naegele's rule).
Pregnancy is counted from your last period, about two weeks before conception, so at conception you're already '2 weeks pregnant'.
Only about 1 in 20 babies arrive on their due date. Your dating scan at 10β14 weeks gives a more accurate date.
Frequently asked questions
When does the second trimester start?+
At 14 weeks. The third trimester starts at 28 weeks.
Is this a substitute for my midwife?+
No. Always follow your midwife's or doctor's dates and advice.