Testing twice a day, about 12 hours apart, gives you the best chance of catching your LH surge, especially if it is short or your cycles are irregular. Once a day can be enough for regular cycles. A positive means ovulation is likely within the next 24 to 36 hours.
It is recommended to do the test twice a day (one after 10am and one around 8pm). First morning urine is not recommended since LH surge may happen later that morning. When you test twice a day you have higher chances not to miss your LH surge.
Liquid intake should be reduced approximately 2 hours prior to testing (no more than 8 oz during these 2 hours).
Another important thing is that for some people a clear positive result may last for a couple of days, for others it can be less than 12 hours. That's why we always recommend testing twice a day so that there is a better chance to catch the surge.
Please note that a positive LH test means ovulation is likely within the next 24 to 36 hours.
When to start, and the best time of day: this page is about how often to test. For which cycle day to begin and a full morning-versus-night breakdown, see our guide on when to take an ovulation test.
“If you have a short or irregular cycle, test twice a day. The surge can come and go in half a day, and that is the group I see miss it most. A steady cycle usually needs testing only once.”
— Inna Galitsky, MD, PhD · medical reviewerFrequently asked questions
Most people use about 5 to 10, depending on your cycle length and how regular it is. You start a few days before you expect to ovulate and stop as soon as you get a clear positive, so a steady cycle uses fewer and an irregular one uses more.
It is unlikely, which is the point of testing twice. A surge can be short, sometimes under 12 hours, so a single daily test can fall in the gap. Testing about 12 hours apart, and within the 10 a.m. to 8 p.m. window, closes most of that gap.
No. Once the test line is as dark as or darker than the control line, you have caught your surge, and testing more will not add useful information. Stop, and focus on timing intercourse over the next day or two.
- American Society for Reproductive Medicine. Optimizing natural fertility: a committee opinion. Fertility and Sterility. 2022;117(1):53-63. asrm.org
- Su HW, Yi YC, Wei TY, Chang TC, Cheng CM. Detection of ovulation, a review of currently available methods. Bioengineering & Translational Medicine. 2017;2(3):238-246.