Pregnancy calendar dating
The calculator on this page can help you work out when you might expect your baby to arrive. As part of your antenatal care, your midwife will also offer you a dating scan that will give you a more accurate date for the birth of your baby.
Use our pregnancy due date calculator to instantly calculate your pregnancy due date.
That's why your due date is calculated based on the date of your last period instead.
Most women ovulate about two weeks after the first day of their period, and conceive shortly afterwards.
If you have irregular cycles you can ask about a 'dating scan' an ultrasound done around the six-week mark, which calculates the due date based on embryo size.
Remember though, that only about 5 per cent of babies arrive on their due date.It is quite normal for a baby to arrive a week or two early or late.