How to work out which day to start testing

If you would like to use a Clearblue Ovulation Test and are wondering when you should start testing, this tool can help you.

Just answer the two questions below and let us tell you when you should start testing.

Select type
When did your last period start? (Optional)
E.g., 25/06/2019

If you don't know your cycle length, we suggest you wait for your next cycle and note the day your period starts (Day 1) and the length of this cycle before using this online tool*.

How long are your cycles on average?

To measure the length of your menstrual cycle, count from the day your period starts to the day before your next period starts.

If you don't know your menstrual cycle length, wait until you've had at least one cycle, then come back to use this calculator. If your cycle length varies by more than three days, choose the shortest cycle you've had in the last six months to work out when to start testing.