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Best Time Of Day To Take An OPK (Ovulation Test) It’s Not When You Think!

hands holding an ovulation test with two lines, one faint trying to figure out what the best time of day is to take an ovulation test

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Odds are we are all familiar with the best time of day to take a pregnancy test (if not, it’s FMU or first morning urine) but, not many women are aware that ovulation tests come with their own set of rules and guidelines. Oh goody!

Figures, right? Nothing comes easy when you’re trying to get pregnant!


Anywho, for those of you that want a quick answer – YES there is a best time of day to take an ovulation test (OPK) and it is pretty much the opposite of what most women think.

You should be testing with OPKs in the late afternoon and or the early evening and if you can test two times a day even better!

Ovulation tests always were my best TTC frenemy. I was never quite sure I could trust them, but at the same time, I leaned on them heavily. It’s that love-hate relationship that I never wanted or knew that I needed.

But, trust me they’re definitely worth your time and should be included in your TTC Arsenal. Especially, If you want to increase your odds of getting pregnant by utilizing LH surge detection, which is probably one of the cheapest things you can do to help you conceive.

How to Use Ovulation Test Strips to Help you Nail Down your Most Fertile Days

OPKs (ovulation predictor kits) are simple to use in theory. If you’ve ever taken a pregnancy test before it’s the same procedure.

Pee on a stick or pee in a cup and dip in the ovulation test strip.
Wait X amount of minutes and read the results. (or if you’re like me hold onto a dry, pee-stained OPK all day so you can check it 100 times like something has changed)

With ovulation tests, you want to make sure you give them the full window of development ie. 5, 10, 15 minutes.


You may throw out the test thinking it’s negative but it has yet to fully develop.

To my knowledge, there is no such thing as an evap line on an ovulation test – doesn’t mean it’s not possible but I have honestly never heard of one.

Best Time of Day To Take An Ovulation Test: The Breakdown


We already know that you need to test at a different time of day than you would with a pregnancy test so we are sure to get the most accurate results.

The first thing you need to do is pinpoint your fertile window, which is going to be based on YOUR cycle – I can not stress this enough!

Even if your friend has the same exact cycle length as you that does not mean that they ovulate at the same time, or that you guys will get a positive ovulation test the same day.

What Cycle Day Should you Sart using Ovulation Tests on?

In my opinion, it is never too early to start testing with ovulation strips.

They are cheap and you can get a pack of 50 for under $15 bucks, there’s just no reason to chance missing the egg.

What cycle day you start testing on is going to depend on your cycle length. I usually suggest that my clients start testing 4 to 5 days out from estimated ovulation.

To figure out what cycle day you should start using OPKs on you need to look at your cycle length. If your cycle is spot on every month, for example, every 28 days, every single month it is a good idea to start testing on cycle day 9 or 10.

For every day over 28 just add a day. If you have a 29-day cycle start using your ovulation tests on cycle day 10 or11, 30-day cycle starts on CD12, 31 starts on CD13, and so on.

Using Ovulation Tests with an Irregular Menstrual Cycle

sunflower that has half of it's petals in bloom while the other half have remained closed.

If you have an irregular cycle like me, you want to adjust your ovulation testing approach a little different than the above but not by much.

You need to look at your cycle as a whole. Take the last 6 months (if you have less data it’s okay) and write down the length of each cycle during that time.

Important: Do NOT use the average on your fertility tracking app.

Once the egg is released it only has 12-24 hours of viability. If your app has you off by even one day because it estimates your 29-33 day cycle is around 31 days your odds of missing the egg increase.

Once you have counted your cycle days for each month take the lowest number of cycle days, in my case 29 and start your ovulation testing on cycle day 11.

I may end up testing for a week before I get a positive ovulation test due to my varying cycle but I know I won’t miss it by testing later in my cycle.

Best Time of Day to Take an Ovulation Test is in the Afternoon & Early Evening

In the majority of women, the lh (luteinizing hormone) is released/synthesized in the body during the early morning hours, which makes it seem like FMU is best.

It’s NOT.

Keep in mind although, the lh surge has been triggered it can take several hours to reach an elevated level to be detectable enough in urine to get a positive OPK.

If you test too early in the day you may only get a faint test line (side note, you pretty much will always get a faint second like on your ovulation test) because the LH has not hit the peak.

You can get a negative ovulation test in the morning, then go and retest on the same exact day in the afternoon and see a full-blown positive.

That being said some women will get positive OPK results in the morning – you are free to test in the morning, but if you do I would not make it your only testing time of the day.

Create An OPK Testing Routine & Stick With It!

When using OPKs you want to be on top of things.

An lh surge can start and end at any moment. Because the window of detection is so narrow, (for some it only lasts a few hours) it is imperative to have a good testing routine.

My routine used to go look like this

  1. Cycle Day 11 started testing with OPKs
  2. Test with FMU then again at 2pm and 630pm
  3. Follow Baby Making Blueprint after positive OPK

To help you craft your own OPK testing plan I’ve broken down some key factors to help you improve your results.

 Figuring Out Your Best Time To Take An Ovulation Test: Q&A Style


What’s the best day to start taking an ovulation test?

Start testing daily about a week after your period has ended on or around CD (cycle day) 8-13 depending on your cycle length.

What’s the Best time to take an ovulation test?

Afternoon or early evening. If you’re looking for actual times I recommend between 11am – 6pm. You should base it off of your schedule. Ie. lunch break & time you get home from work.

How many times a day should I test with OPKs?

For optimal results test twice a day, at the SAME TIME every day, in the afternoon & early evening if possible. If you are only able to test once a day that is fine too. I used to test at 2pm and 630pm.

Can diluted urine affect ovulation test results?

Diluted urine can cause inaccurate results. It is best to limit fluids for the holding period to ensure your results are reliable.

That being said, do not dehydrate yourself.

When I say limit fluids I mean don’t go and drink two bottles of water and a 32oz coke an hour before you’re scheduled to test.

Do you have to wait 4 hours to take an ovulation test?

Aka – ‘Should I hold my pee before taking an ovulation test?’ Try to plan on holding it for at least 2-3 hours before you test.

This helps build up the concentration of the urine and makes the LH surge easier to detect. Again – do NOT hold it until you are in agony or any type of pain be reasonable.

There have been times I’ve even gone and emptied half of my bladder in the middle of my hold time. Do what you have to do.

How many days will you get a positive ovulation test?

Most people only get a positive ovulation test for one day, maybe two.

There was one month for me when I was trying to conceive my first child that I got 4 days in a row of positive OPKs.

That just so happened to be the month I got pregnant, but I tend to wonder if my body was actually having trouble that month releasing the egg and that’s why it lasted so long. Either way, it was a win for me!

How soon after a positive ovulation test will I ovulate?

A positive ovulation test indicates that ovulation is 12-24 hours out in most cases. But, like I said it can depend.

Some recommend you just stop testing after you get your positive and count the next cycle day as 1DPO (1 day past ovulation). I can not do that. I have to test until I see that negative – maybe a cruel form of self-torture?!

Should I wait for a positive ovulation test to have sex?

No, absolutely not. Even though ovulation tests are helpful you CAN still ovulate and get a negative all month long. If you can’t seem to get a positive still make sure you’re having sex and trying to catch that egg!

How do you know if your OPK is positive?

woman sitting on a bed trying to see if her ovulation test is positive

Your OPK is positive when the test line is as dark or darker than the control line.

A lot of women dismiss a result when the test line is as dark/bold as the control line as a negative result – when in doubt act like it’s a positive and start getting busy. You do not want to miss your fertile window by misreading your test result. You’re also welcome to join the P is for Pregnant, TTC support group and post a picture of your test to get some help deciphering your OPK results.

Remember, your OPK is negative until both the test and control line are even in color or darker. You will most likely always have two lines on the ovulation test, with the test line ranging from extremely faint to just under the control line color.

When catching your lh (luteinizing hormone) surge, time is of the essence.  Many women only get a positive OPK for one day,  and even that can vary by hours. By mapping out a plan that fits your schedule you are unlikely to miss the lh surge.

Do you have an ovulation testing routine now? Will you be changing it? Share your routine!

Now that we have figured out the best time of day to take an ovulation test and broken down some of the nitty-gritty stuff that goes along with it all that is left to do is put your newfound knowledge to practice and get that BFP!


Ahmad F. Khattab, Fayez A. Mustafa, Philip J. Taylor; The use of urine LH detection kits to time intrauterine insemination with donor sperm, Human Reproduction, Volume 20, Issue 9, 1 September 2005, Pages 2542–2545,

 Martinez AR, Bernardus RE, Vermeiden JP, Schoemaker J (1994). “Time schedules of intrauterine insemination after urinary luteinizing hormone surge detection and pregnancy results”. Gynecol Endocrinol. 8 (1): 1–5. PMID 8059611

Wikipedia contributors, “Luteinizing hormone,” Wikipedia, The Free Encyclopedia, 

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