When to start Ovulation testing

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.

When did your last period start?
E.g., 29/11/2021
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.
Tell me when to start testing

You should start testing on

You should start testing 17 days before you expect your next period

Clearblue Digital Ovulation Test
Over 99% accurate in pinpointing your 2 most fertile days* – with unmistakably clear digital results
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 {DAY_TEST_DOT} with {DOT_NAME},
on Day {DAY_TEST_ADOT} with {ADOT_NAME},
on Day {DAY_TEST_COTS} with {COTS_NAME}.

Count the first day of your next period as Day 1

Your personal cycle information

Start of your last period
Your usual cycle length:
Results are based on the information you have provided.
Change my information
  • * If you wish to start using Clearblue Ovulation Tests before you know your cycle length, we recommend that you start testing on Day 10. However, without determining your cycle length, it is possible that you may miss your LH surge because you have started testing too late, or you may need to start a new pack to continue testing.

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