When To Start Ovulation Testing - Clearblue

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When to start testing for ovulation? When did your last period start? E.g., 17/02/2026 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? Don't know <20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 >41 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

with Clearblue Digital Ovulation Test Over 99% accurate in pinpointing your 2 most fertile days* – with unmistakably clear digital results Add to my calendar

In this cycle, you’re 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.

You should start testing on your next cycle

Cycle day default_11 with Clearblue Digital Ovulation Test Over 99% accurate in pinpointing your 2 most fertile days* – with unmistakably clear digital results Count the first day of your next period as Day 1 Discover

Your personal cycle information

Start of your last period
Your usual cycle length:	days

Results are based on the information you have provided. Change my information

This tool is for guidance purposes. Always use the leaflet provided with your product to work out when to test.

• * 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.

How to get pregnant faster?

Having sex at the right time of your cycle is key, so identifying your fertile days with an ovulation test will help you get pregnant faster.

Discover our Ovulation Tests now