How to determine 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.
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 Ovulation Calculator tool*.
When did your last period start?
E.g., 08/10/2019
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*.
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.
You should start testing on
You should start testing 17 days before you expect your next period
You should start testing on
You should start testing 20 days before you expect your next period
You should start testing on
You should start testing 20 days before you expect your next period
In this cycle, you've missed the ideal date to start testing.
We advise you to wait for your next cycle before using Clearblue Ovulation Tests, as it is possible that you missed your LH surge in this cycle. In your next cycle you should start testing on Day 6. Count the first day of your next period as Day 1.
We advise you to wait for your next cycle before using Clearblue Ovulation Tests, as it is possible that you missed your LH surge in this cycle. In your next cycle you should start testing on Day 6. Count the first day of your next period as Day 1.
Your personal cycle information
| Start of your last period | |
| What’s your usual cycle length? | days |
Results are based on the information you have provided.