Pregnancy Calculator

If you’re eager to know when your baby is expected to arrive, our pregnancy calculator can help you work out your due date.

Simply enter the date of the first day of your last period and the average number of days between periods (i.e. the length of your cycle), and the calculator will do the rest.

The possible conception date is the estimated date that fertilisation was likeliest to have occurred. Conception will happen shortly after ovulation, which you can work out using our ovulation calculator.

You should take a pregnancy test the first day after your missed period, as this is when the test will be most reliable. A pregnancy test can be obtained from your GP free of charge.

The average length of a pregnancy is 40 weeks, or 280 days. This is based on the average cycle length of 28 days. The gestation period will change based on the length of your cycle.

Please keep in mind that our pregnancy calculator will only provide you with estimated dates based on averages. It’s common for your baby to arrive within a week of either side of their due date. Your midwife will offer you a dating scan as part of your antenatal care, which will provide you with a more accurate due date.

Pregnancy calculator

Please enter the date of the first day of your last period

Days in between periods

First day of the your period
Possible conception date
When to take a pregnancy test
Average gestation (days)
Possible birth date