How to Use Blacklight for Cat Urine Detection?

Instead of sniffing your house in the hope of finding the spot where your cat urinated invest in a UV blacklight for cat urine detection. Using the best cat urine detector will make the pee stain glow in the dark so that you can find it and clean it quickly and without a hassle.
Best Blacklight for Cat Urine Detection

As a cat owner, you must be familiar with that strong and unpleasant smell of cat urine floating around your house. You can’t see it, but you know the dried pee stain is out there somewhere! Failing to clean the affected area properly can result in your cat peeing repeatedly at the same spot.

A blacklight can be handy in such situations. It is an essential tool that every cat owner needs to find cat urine stains around the house quickly and easily. You can get it in most hardware stores (or buy one online from here).

In this article, we will explain what type of black light you need and how you can use a UV blacklight for cat urine detection.


What is a Blacklight and How Does It Work?

Blacklight is also known as ultraviolet or UV light. The term blacklight means ‘not visible to the human eye’ (due to higher light frequency).

Light Visibility Spectrum - Blacklight for Cat Urine
By Philip Ronan, CC BY-SA 3.0

It works by emitting ultraviolet rays that cause some chemical compounds to glow in the dark.

Does Blacklight Show Cat Urine?

Yes, a blacklight will show cat urine. In fact, black light has been used to find out hidden stains for a very long time.

Cat urine will glow under a black light making it super easy to see where exactly that unpleasant odor in the house is coming from. Once you spot it, you can use enzymatic cleaners to clean the area effectively.

Why Does Cat Pee Glow in the Dark Under a Blackight?

Bodily fluids contain phosphorus along with other substances. When phosphorus in the cat urine reacts with oxygen in the air, it glows yellowish green. The intensity of the glow is increased under a UV blacklight.

This way, cat pee stains become easily visible so that you can clean them asap! Even other bodily fluids will glow in the dark under the UV light.

Here is an informational resource that explains what makes cat’s pee glow when exposed to blacklight.

You should know that a blacklight is not just useful in finding cat urine stains.

What Else Can a Blacklight Detect?

Besides invisible cat urine stains in your house, a blacklight can help you uncover other organic compounds like feces, vomit and cat spray spots. Even paint, hair dye and some currency notes will glow under black light.

Black lights are often used for entertainment purposes such as nightclubs and raves where they illuminate glow sticks and other items.

Just get your hands on the best cat urine detector and shine it in a dark room to watch the magic happen!

However, keep in mind that not all blacklights work equally well.

Will Any Black Light Detect Cat Urine?

No, not just any black light will detect cat urine. You need blacklights with wavelengths between 365-385 nm.

Many black lights have wavelengths outside this range and fail to reveal cat urine stains. Which is why it’s essential to check whether the blacklight you are going to buy has the correct wavelength range to show cat urine stains.

UV Blacklight for Finding Cat Urine: Buying Considerations

Cat pee stains not only make your house smell bad, but also compel your cat to continue marking the same area repeatedly.

There are some programs like this one that can help you break this bad habit.

But in the meantime, it is really a shame to throw money on frequent carpet steam cleaning only because you couldn’t locate and clean the stain properly in the first place.

Using a blacklight for finding cat urine can help you stop to your cat’s inappropriate peeing behavior once and for all!

Here is what you need to consider while buying a blacklight specifically for finding pet urine stains.

Light Wavelength (Output)

Most black lights come with the information about their wavelength. You will see LED lights with wavelength of 390-400 nm. However, these are not ideal for cat urine.

If you want a blacklight for cat urine, you should look for ones that have wavelengths between 365-385 nm range.

Strength of the Light

When it comes to buying a UV blacklight for cat urine, the strength and the type of the bulb is important. The strength of the UV light indicates how powerful the bulb is.

The more powerful the bulb, the brighter your cat’s urine will glow and will be that much easier to find. So, look for a black light with high powered LED lights.

Number of LED Lights

The number of individual bulbs your light has is also an important factor. Devices with more LED lights have stronger UV lightning and make urine stains clearly visible.

Most blacklights feature anywhere from 50-100 LED lights within a single flashlight. Although as few as 9-12 are sufficient for finding pee stains if they are powerful enough!

Comfortable Grip and Lightweight

Since blacklights are used to find stains on the floor and furniture around the house, they must be comfortable in your hands and lightweight. You don’t want a blacklight that is too heavy or uncomfortable to hold for a long time!

A black light with plastic body and rubber grip works well in this regard. Also check if the controller comes with adjustable angle options to suit your needs!

What’s the Power Source?

Well, black lights work on batteries, and you can buy black lights that run on normal batteries. The choice of the power source is really a matter of convenience as well as affordability for you.

If your blacklight can use rechargeable batteries, it will be more convenient and economical than buying new ones all the time!

Are Goggles Included?

Prolong exposure to strong UV light can be bad for your eyes. If you have a bigger house, finding your cat’s pee stains will take more than just a few minutes. So, you should look for a deal that offers protective glasses as well.

Besides protecting your eyes from UV light, these will also let you to see the stains more clearly.


The black light you are going to buy must be affordable. There is no point investing in the most expensive blacklight you can find if it fails to show cat urine stains under blacklight.

So, look for black lights with all the features you want but with a reasonable price tag!

Best Black Light for Cat Urine Detection

As mentioned above, light wavelength is an important feature to look for while buying a blacklight for finding cat urine stains. The best cat urine detectors should have LED lights with wavelength between 365-385 nm.

Higher wavelengths will also work but won’t make the pee stains glow as bright. Which means spending more time to find the urine stain.

To find your cat’s pee stains quickly and easily consider buying one of the following UV flashlights!

1. KOBRA UV Black Light Flashlight

If your cat is a repeated offender the KOBRA UV Black Light Flashlight is a device, you need to have. Due to its extreme power, you will no longer have to crawl over stinky carpets to pinpoint the pee stain’s location.

The 100 LED bulbs create a wide beam that will help you check your house and find urine stains in no time. This device has a wavelength strength in between 385 and 395 nm and will make both old and new urine stains glow visibly.

KOBRA Black Light Flashlight 100 LED Lamp and Blacklight For Home & Hotel Inspection, Pet Urine & Stains - Ultra Intensity 18W 385-395nm LEDs Spot Counterfeit Money, Leaks, Scorpions (100 LED)

$22.95  in stock
1 used from $21.91
Free shipping
as of January 30, 2023 7:36 PM

Besides shedding light on all your cat’s accidents, this flashlight can also help you detect leaks and find scorpions. And if you are at any point unsatisfied with this flashlight’s performance, you are covered with a 1-year money-back guarantee.

According to the customers, this is the best blacklight for finding cat urine because it also works for finding vomit and feces. Due to high-power, the batteries don’t last long. But that is to be expected with such an efficient device.

Read All Customer Reviews >>

2. LIGHTFE UV Flashlight

The LIGHTFE UV Flashlight is a waterproof, lightweight and quality device that will help you find urine stains no matter how old they are. Unlike other blacklights, this one has one high-quality LG UV LED light.

This blacklight is powered by batteries and has a strong beam that will make stains easily visible. Hence, you won’t actually have to kneel on a soiled carpet or inhale the toxic pee odor where it is the strongest.

LIGHTFE Black light UV Flashlight 365nm blacklight UV301D with LG LED Source,Black Filter Lens, Max.3000mW high power for Resin Glue Curing Light, Rocks and Mineral Glowing,A/C Leak Detector

 in stock
1 used from $32.18
Free shipping
as of January 30, 2023 7:36 PM

This device has a lifespan of 10,000 hours and a pen-like design so you can keep it close by at any time. Thanks to a wavelength of 365 nm, all your cat’s offenses will glow bright, and you will be able to find them fast and clean them properly.

The actual beam is smaller compared to other blacklights on the market. So, it takes more time to sweep larger areas. On the other hand, it is a great tool to have thanks to its portability, ease of use and design.

Read All Customer Reviews >>

3. PeeDar UV Pet Urine Detector

As its name suggests, the PeeDar UV Pet Urine Detector is made exclusively to detect invisible pet stains immediately. The optimized wavelength of 380-385 nm is more efficient at detecting cat urine stains making them glow brightly.

This device comes with a 21 LED lights. These may seem less but remember that as few as 9 will also do the job. The great thing about this blacklight is that it comes with batteries. So, you can start looking for pee stains as soon as you get it out of the box.

PeeDar 2.0 UV Pet Urine Detector Black Light Flashlight + Cat & Dog Behaviorist Book + 3 AAAS. Ultra Bright Optimal 380-385NM LEDs Find Invisible Stains Instantly! Rid Cat, Dog Pee Issues Forever.

$19.90  in stock
as of January 30, 2023 7:36 PM

The PeeDar UV Pet Urine Detector is water resistant and can work for 5 hours non-stop, but hopefully, your cat didn’t make such a mess that you will have to. Like any other black light, the PeeDar works best in complete darkens, but you can also use it during the day with closed curtains.

If you buy this blacklight you will also get an Exclusive Expert Pet Behaviorist eBook that will help teach your cat to stop urinating outside the litter box. And wouldn’t it be nice to get rid of all your problems with just one purchase?

Read All Customer Reviews >>

4. uvBeast NEW V3 365nm Black Light UV Flashlight

The uvBeast NEW V3 365nm Black Light UV Flashlight is a high-intensity device that promises to find all urine stains without being bulky. It is powered by rechargeable cells at 2600 mAh. It comes with a two-bay USB charger and a mains adapter to go with it.

It is the highest intensity 365 nm device from uvBeast yet. So, you can do a close-up, sweep the entire room, or work in the ambient light with a single flashlight.

uvBeast NEW V3 365nm Black Light UV Flashlight – HIGH DEFINITION Ultraviolet - Rechargeable 18650 – HIGH POWER and LONG RANGE Professional Grade Beam Best for Professional/Commercial Use – USA Stock

$79.99  in stock
as of January 30, 2023 7:36 PM

The uvBeast has a 365 nm wavelength. And the powerful triple LED lights will make even the nastiest stains glow. The great thing about uvBeast Flashlight is that it comes with special PCB.

In a completely dark room, the uvBeast works like a beast and makes pee stains clearly visible.

Read All Customer Reviews >>

How to Find Cat Urine with a Blacklight?

Once you get your hands on the best blacklight for cat urine, it is time to investigate what your kitty was up to. If you never used a blacklight before to find cat pee stains, here are a few tips to make this process easier for you.

To find cat pee quickly using a blacklight follow these steps:

Step 1: Wait Until It Gets Dark in the Evening

While you can draw all the curtains in the room, it will always be easier to wait until it gets dark to use the UV light.

Once it gets dark and you are ready to start, turn off all the lights in the room and all the adjacent rooms or hallways. Remember you need complete darkness, otherwise, you might miss some of the stains.

Step 2: Check the Most Probable Areas First

Locate the area where the pee smells the strongest and start from there. You might need to sweep back and forth for a while before you find the stain.

To make the search even efficient, start searching near the area where you think your cat may have urinated and then work outward. Here are some of the most common areas you can start with:

  • Around, behind, and underneath furniture such as sofas or beds.
  • Near the cat’s food bowls and litter box.
  • Underneath carpet edges and floorboards.
  • Along baseboards, walls or in any cracks you find.
  • Area where you have previously caught your cat peeing or spraying.

Step 3: Look for a Glowing Yellow or Green Spot

When the UV light falls on the urine stain, it should glow. Depending on the amount of urine there was, the stain may look like a puddle, spot, drips, or splatter.

Since other substances can glow under the blacklight as well, look at the size and shape of the stain to determine if it is in fact cat pee.

Step 3: Keep Checking Other Places

Most cat owners make a mistake of cleaning the first stain they find and think the job’s done.

Don’t assume that your job is done after you find the first pee stain. Cats sometimes pee on various surfaces. So, move the light along the walls, furniture, curtains, and all corners of the room.

Cat urine can be found almost anywhere, so you need to keep looking until you find all the stains!

Step 4: Remember to Mark the Stained Area

It can be hard to remember the exact size and location of the stain, let alone few of them when the lights come back on.

Therefore, use a tape or chalk to mark the perimeter around the stain while you have the blacklight on. This way you won’t miss anything and will finally get rid of that nasty pee odor.

Why Does Cat Urine Not Show Up Under a Black Light?

There may be times when you are not able to see the cat pee stains under the blacklight even when you know they are there. This may happen due to several reasons.

  • Check if the blacklight wavelength is correct. As mentioned above, if you need a blacklight for cat urine detection, you’ll need one with wavelength of 365-385 nm to see pee stains clearly.
  • Confirm that the cat pee has completely dried up. Dry urine glows best. If moisture is still present, it reduces the glow making it harder to spot pee stains.
  • Check if the batteries are still working. If not replace them and try searching again.
  • You are not searching in complete darkness. The blacklight is less effective under bright lights or during the day.
  • You are not getting the blacklight close to the area or surface you are inspecting.

Here is a useful resource that explains this matter in more detail.

How to Find Cat Pee Without a Blacklight?

Maybe you are waiting for your blacklight to arrive, and your cat decided to pee somewhere in the house, again. Obviously, you can’t spend precious hours doing nothing!

It can be tricky to locate cat pee without a blacklight, but there are ways to do it. You’ll need a good sense of smell, some white vinegar and water, and a spray bottle. While your options are limited, here is how to find cat pee without a blacklight.

Monitor Your Cat and Look for Signs

If you can, keep an eye on your cat when they are in the house. If you see them start to walk in a certain direction, or if they go into a certain room, chances are they are going to pee. If you can stop them in time, you can prevent the mess altogether.

Sniff It Out

Desperate times call for desperate measures and you will need to rely on your nose to find the cat pee spots. Try to identify the room the cat urine smell is coming from first and then check all the usual places.

Often, the urine will be in a specific spot where the cat has been known to go. Plants, corners, carpets and sofas are some of the places cats like to go the most.

If you are lucky, one of these locations will be your crime scene. If there is an odor present, it is likely cat urine.

If not, continue sniffing until you find it!

Look for Stains

Obviously, this will work only if you have lighter furniture or carpets. Also, don’t forget to look under the furniture and on the walls.

Puddles are an obvious sign that the cat is peeing in a certain area, and you will probably find some older stains there too.

If you can identify the spot where your cat has urinated, pour white vinegar and water onto the area. Don’t forget to test it on an inconspicuous spot first!

Be sure to saturate the area well, so that the smell is eliminated. Let the area dry before you start cleaning it.

If you are not able to find the pee spots, you can still try to cover the smell with vinegar. The vinegar will help to neutralize the urine odor. Just mix water and white vinegar in a spray bottle and spritz the area.

It will not work for long, but it is a better solution than doing nothing.

Hopefully, one of these tips will help you find the cat pee before it becomes a big mess. And don’t forget, if all else fails, there is always the blacklight!

So, You’ve Spotted the Cat Pee, Now What?

So, you used the best blacklight for cat urine detection and you found pee stains (usually more than one!), now what? Seeing all those stains can be shocking at first. But look on the bright side. Now you can finally clean all of them once and for all!

While you can use baking soda, hydrogen peroxide or any number of cleaning products, nothing is really effective at removing pee stains as enzymatic cleaners. These products break down enzymes in your cat’s pee and get rid of the nasty smells permanently.

For the best results, spray the enzymatic cleaner on the pee stains (that you have marked with a tape or chalk) and beyond its edges and let it sit for 20 minutes. After that time bloat any excess and let the area dry.

If the smell is still after the area is dry, use your cat urine detector and check the room again. Maybe you missed a pee stain during the first round!


Here are some frequently asked queries from cat owners about using blacklight for cat urine detection.

Can UV Black Light Detect Old Cat Pee Stains?

If the blacklight detects black or brown spots when you are in complete darkness, these are probably old stains that don’t glow much under blacklight. However, they will still have that distinctive awful odor.

Will a Black Light Always Detect Cat Urine?

As mentioned above, there are situations when using a blacklight for cat urine detection does not work. Things like age of the pee stains, urine concentration, and other factors can influence blacklight effectiveness.

Can You Spot Cat Spray Under a Black Light?

Yes, black light will detect cat spray stains as well.

Can You Use an iPhone Flashlight to Detect Cat Urine Stains?

No. iPhone flashlights don’t emit the blacklight wavelength needed to detect cat urine stains. There are some DIY videos out there showing how to transform an iPhone flashlight to UV lights.

The following video shows if this hack really works!

Can You Find Cat Urine with a Blacklight App?

No, blacklight apps are not blacklight detectors. They are just apps that apply black light filters to pictures taken with the app’s camera.

What Are Cat Urine Detector Pens?

Cat urine detector pens are black lights attached to a pen-sized tube. These devices give you great portability so you can spot pee stains in any room (like a hotel room you are staying in) or on any surface.

How Much Does a Blacklight for Cat Urine Detection Cost?

Buying a blacklight for cat urine detection is very affordable, and you can get one for $20-$35 bucks or less. Check out the list of best blacklights for finding cat pee above.

Can Black Light Detect Urination Outside the Litter Box?

Yes, black lights can even be used to detect cat urination outside of litter box. In fact, blacklight is one of the best tools for that use!

Can Cat Spray Be Removed with a Blacklight?

Unfortunately, blacklights cannot remove cat spray just find it. You can try some cleaning products or enzymatic cleaners, but they may not always work.

Can You Get Rid of Cat Pee Smell with Black Light?

As mentioned above, blacklights will only reveal substances that glow in complete darkness. So no, black light won’t help in get rid of cat pee smell.

Does Black Light Work on White Carpets?

Yes, black light works well both on carpets, and hard floors. For black light to work properly it needs darkness. That’s why black lights should be used at night!

During the day black light is less effective. This effect is even stronger with white colored surfaces because they reflect more of the black light. Hence blacklight doesn’t work on them as well during the day.

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