What Fabrics Block UV Rays?

What fabrics block UV? Rayward Apparel

Your clothing is more than just a fashion statement, it helps keep you protected from damaging UV radiation – one of the leading causes of skin cancer. Certain types of materials, like bamboo shirts, often come with a higher UPF rating (less UV rays can pass through), but it depends on a lot more factors than just fabric composition. Every product is different, some provide superior protection while others provide little to none. If you are shopping for sun protective clothing and do not see a UPF value listed, keeping the below factors in mind will help make sure you are selecting a product that will help keep you protected.


Fabric Spools
  • Fibers: The fibers themselves have different UV protection qualities. Synthetic fibers such as nylon and polyester generally have a higher UPF value than other popular fibers such as bleached cotton. Bamboo fibers (when purchasing bamboo shirts it’s generally labeled as viscose from bamboo) also tend to have a higher UPF value than cotton. However, the process of turning bamboo into bamboo viscose can sometimes alter the properties of the fabric, so make sure to check for a UPF rating whenever possible and not make any assumptions.
  • Construction: Ultimately the goal is to reduce the amount of light that can pass through. With a tight weave, you have less space between the threads and thus less potential for UV radiation to pass through. Also, a shirt’s thickness can also help protect your skin as it often has more fibers per square inch and much tighter weave. A good simple test is to hold a shirt up to the light – if a lot of light is passing through it likely has a lower UPF rating than a shirt where no light passes through.


Generally speaking, loose-fitting apparel is preferable to tight clothing. Tight clothing has a tendency to stretch which separates the fibers – allowing more light to pass through. Loose unstretched fibers are going to provide more consistent protection, and are also less likely to become permanently stretched over time, therefore maintaining their UPF protection rating for longer. This also helps determine whether a shirt will maintain its UPF rating after being washed.


The more coverage the better. It goes without saying that a short sleeve shirt cannot keep your entire arm protected, so try and find products that maximize the surface area coverage. Long sleeve bamboo shirts are great, and hooded long sleeve shirts offer even more protection for your ears and neck.


Fabric Colors Bamboo Shirts

Darker is better, but there is no formula for determining which specific color is best for sun protection. If you have to choose between a black and white shirt and are looking for maximum UPF value, more often than not the black shirt will provide more protection. This is in part due to the color absorption properties, but also due to the process of coloring a fabric with different dyes which further reduce the amount of UV radiation that can pass through. But keep in mind – just because a shirt is white does not mean it is not keeping you protected. A shirts protective qualities is a combination of all of the above factors and it’s very possible that your white bamboo shirts are keeping you just as protected, if not more protected than your black cotton shirts. 

UPF Rating

The safest way to make sure you are protected is to buy products with a posted UPF rating. This means that the shirt has been tested and proven to have UV protective qualities. For maximum protection, look for apparel that has a UPF 50+ rating.

What Color Is Best For Sun Protection?

Rainbow for Sun Protective Clothing

There are a lot of different factors that play into the UV protective rating of a shirt. Fit, fabric composition, weight, density, and sometimes even color. However, determining whether or not specific colors are more protective than others is not as easy as it seems. Continue below to see how color impacts the UPF of sun protective clothing.

Darker or Brighter is Generally Better

Hot coals

Dark and bright colors attract and absorb more light than their lighter counterparts. So if you don’t own any sun protective clothing and want to get as much protection as possible – lean towards the darker and brighter clothing options. However, this also comes with a downside. The darker the color, generally this also means it will generate the most heat. This can be particularly uncomfortable if you live in the south during a hot summer. The following YouTube video does a great job representing this dynamic using various colors of crayons in the sun:

So you want to stay protected, but you don’t want to bake inside your own shirt. Especially when you are actively exercising or playing sports, this can be a deal breaker. Good news is, you don’t have to choose between being protected and being comfortable. There are plenty of light colored sun protective clothing options out there providing excellent protection. You just have to make sure it has the UPF rating listed. Here at Rayward Apparel all of our products are certified at UPF 50+.

Color Can Sometimes Be Misleading

As mentioned previously, there are many different factors that play into the UPF rating of a fabric. If the shirt is too thin or stretched extremely tight you are likely not going to receive proper protection regardless of the color. The same goes with many of the other factors – if a shirt is severely lacking in one it’s possible the color will have very little impact. If your white shirt is UPF 3 and black shirt is UPF 4, that’s still well below the recommended protective value. Although it may seem odd, In these circumstances it’s best to simply wear sunscreen underneath your shirt to stay protected.

Color dye sun protective shirts

Also, while different colors have different UV absorption qualities, it’s not always that straightforward. The color of a shirt is made through a variety of color dyes. Sometimes the dye itself can have a bigger impact on the UPF rating than the color – so it’s possible your light grey shirt has a better protection rating than your black shirt. However, the only true way to determine the true UPF value of a fabric is to have it lab tested. All sun protective clothing with a listed UPF value should have been tested and certified accordingly.

UPF 50+ Sun Protective Clothing Provides Excellent Coverage Regardless of Color

In summary, while the color of a fabric certainly has an impact on the UPF rating it’s difficult to determine its true protective value without knowing it’s UPF rating. While all clothing has some level of UPF, oftentimes it’s far less than needed. If you are trying to make sure you get proper coverage, your best bet is to simply purchase clothing that has been tested at UPF 50+. Regardless of the color, if your sun protective clothing has been properly tested at UPF 50 you can rest assured knowing you are well protected.

Can UV Go Through Clothes?

UV Shirts Exposure, Sunlight over field

So can UV go through clothes? In most cases – yes. But it’s not necessarily if UV can pass through that you should be asking, but how much UV can pass through.

UV radiation is the leading cause of most skin cancers, so it’s important to protect yourself. However, UV exposure is tricky because it’s not possible to see with the naked eye. Just because visible light is not passing through an object or fabric, that does not necessarily UV light is being stopped. And the opposite is true as well – UV protection shirts might be lightweight and seemingly thin – allowing light to pass through, but this doesn’t necessarily mean they allow UV radiation to pass through as well. A great example of this is sunglasses that block 100% of UV radiation. You can clearly see through them, yet UV radiation cannot pass through at all. 

The video to the right shows what the world looks like through a UV camera, or in UV light instead of visible light. It’s an interesting way to show how seemingly invisible factors impact the amount of UV light that can penetrate something. Around the 1:34 minute mark of the video they show a pair of glasses in both visible light and UV light side by side – a great way to see the imperceptible differences. A similar concept applies to fabrics – just because you can’t see through a fabric does not necessarily mean UV radiation is not passing through.

So how are you supposed to know how much UV radiation is penetrating your clothing? And if you have a UV protection shirt, how much protection is that providing?

UPF Rating for UV Protection

The only way to know the true protective value of a fabric is if it has a UPF value listed. UPF stands for Ultraviolet Protection Factor and is a rating very similar to the SPF ratings you’ll see on sunscreen, but is applicable only to fabrics (read our full explanation of UPF and how it differs from SPF). 

To list a UPF rating a product must first be lab tested according to industry standards which will show the exact amount of UV radiation which can penetrate that fabric. A rating of UPF 30 means 1/30th, or about 3.33% of UV light passes through. And UV protection shirts with a rating of UPF 50 means 1/50th, or about 2% of UV light passes through. The standard categories you may see listed are below:

UPF RatingProtection Category% UV Radiation Blocked
UPF 15 – 24Good93.3 – 95.9
UPF 25 – 39Very Good96.0 – 97.4
UPF 40 – 50+Excellent97.5 – 98+

At Rayward Apparel, we believe all sun protective products should have a rating of at least 50+, providing you the highest possible level of protection. To learn more about our full line of UV protection shirts and accessories, visit our online shop.

Hooded UPF 50 Bamboo Blue Shirt Rayward Apparel
Mens SUN BOUND Hooded UPF 50+ Shirt

Fit and Fabric

If a shirt is specifically designed with skin protection in mind, it likely has a UPF rating listed. However, the vast majority of products you’ll find will not have anything rating listed – so how are you supposed to know how much UV light is passing through? While it’s impossible to say an exact amount, there are certain factors you can look for which can help in making a determination. Our companion post summarizes which fabrics block UV rays, but if you look for the features outlined below, you’ll be off to a good start:

  • Materials: Synthetic fibers such as nylon and polyester often perform better than bleached cotton shirts. Also many UV protection shirts are made of bamboo viscose, which is shown to be more absorbent than a standard cotton.
  • Construction: The tighter the weave the better.
  • Fit: Loose fitting is generally better than tight fitting as it’s not going to be stretched out
  • Style: The more coverage the better. Choose long sleeves over short sleeves.
  • Color: Generally the darker the better, but it’s not always the case.

The best way to make sure you stay protected is to buy shirts that have been designed to keep you that way – protected. UV radiation can damage your skin even through clothes, so make sure to keep that in mind whenever you are out in the sun.

Top 5 Questions (and Answers) on Sun Protection

Motorboat with Sun Reflecting on the Water

It’s important, we spend a lot of time in it, and yet there’s still a lot of confusion about how to protect ourselves from it. We’re talking about the sun, of course! Our goal below is to highlight the top five questions regarding sun protection, and in doing so, hopefully clarify a few important sun safety tips. One thing that is clear? Rayward Apparel’s Sun Bound shirts and sun hoodie are your go-to sun protection apparel! Find out why while learning more about sun protection below:

1) What Causes Sunburn and Skin Damage?

Sunburn is caused by ultraviolet (UV) rays penetrating your skin. UV damage comes from two forms of UV rays: UVA and UVB. UVA rays penetrate deeper into the skin and are what cause wrinkling, early aging and, most critically, skin cancer. UVB rays damage the surface of the skin and are what cause sunburn and reddening. Too much exposure to either UVA or UVB rays will damage your skin and increase your risk of skin cancer.

2) What Affects My Risk of Sun Damage?

Your risk of sun damage, whether permanent or temporary, depends on a few factors, including the amount of time for which you are exposed. The time, environment and weather also play a role in determining how much exposure is too much. The sun’s rays are most powerful between 10 AM – 4 PM, for example. Also, you’ll burn easier at higher altitudes or closer to the equator. Furthermore, consider your surroundings and any surfaces that could reflect UV rays, such as water, ice, sand and concrete, especially onto your face.

Woman at Beach with Sun Protection

3) What Is the Best UPF Rating?

Ultraviolet Protection Factor (UPF) measures the amount of UV radiation that goes through a fabric and reaches the skin. The higher the UPF rating, the better, and the best is UPF 50+. To translate a UPF rating into practical application, a UPF-rated fabric lets a percent of UV rays through equal to one divided by the UPF rating (1 / UPF). For example, a UPF 50+ shirt lets through less than 1/50th, or less than 2%, of UV rays. Additionally, the UPF rating system, unlike the SPF system for sunscreens, measures protection against both UVB and UVA rays.

4) How Do Sun Shirts Block UV Rays?

UPF sun shirts and sun hoodies block UV rays by shielding your skin. This protection can be accomplished a few different ways. Dyeing with darker colors, for instance, will absorb more UV rays, therefore allowing less to reach your skin. Certain fibers, like the blend of viscose from bamboo and cotton used in our sun hoodie, have natural properties and a dense weave that absorbs UV. NOTE: Some companies achieve their UPF ratings through chemical and oil treatments which can be bad for the environment and less durable.

5) What’s the Most Effective Sun Protection?

The most effective sun protection is the one that you wear when you need it. To us, that means the reliable, comfortable and always broad-spectrum UV protection provided by UPF apparel, like our sun hoodie. There are many reasons we like UPF clothing more than just sunscreen for effective sun protection. For starters, with properly worn UPF apparel, you can’t accidentally miss a spot, you don’t have to reapply and it’s easier to remember to put a shirt on! Plus, you’ll save money in the long run and your protection is always broad spectrum.

Men's Sun Bound Hoodie in Blue

If you have additional questions about sun protection, leave us a comment below! To shop our UPF 50+ Sun Bound collection of sun shirts, including a t-shirt, long sleeve shirt and sun hoodie, CLICK HERE.

What Is The Best Sun Protection Clothing?

Paddleboarding on River at Sunset

The most reliable sun protection comes from quality UPF apparel, but what makes for the best sun protection clothing? Not all apparel offers equal protection against damaging UV rays. In fact, some of the clothing labeled and rated for sun protection isn’t ideal for active wear. Shirts with UV protection should be comfortable, stylish, versatile, long-lasting and, above all else, UV protective. Continue below as we dig deeper into what makes for the best sun protection clothing.

Comfortable Sun Protection Clothing

The perfect sun protection clothing needs to be as comfortable as it is protective. You want a shirt so comfortable that you’d wear it even if you weren’t leaving your house. All too often, choosing a shirt with UV protection means sacrificing comfort for the sake of a higher UPF rating. This is how you end up with sun shirts that feel like plastic, aren’t breathable and fit poorly. In reality, comfort and protection should go hand in hand. Fortunately, Rayward Apparel’s blend of viscose from bamboo provides the best of both worlds for an ultra soft buttery feel that still ensures a UV shield rated at UPF 50+.

Bamboo forest

Stylish UPF Apparel Designed for Any Occasion

The best sun protection clothing also needs a stylish design and quality finish. Without style, even your most protective shirts with UV protection would just sit in your dresser. With this in mind, Rayward Apparel’s Sun Bound Collection is designed with a modern, athletic fit that looks as good as it feels. Plus, a timeless raglan sleeve and tagless collar round out the design. The result? What we believe to be the best t-shirt, long sleeve shirt and hooded shirt for all day sun protection. Speaking of which…

Versatility Equals Utility

Ideal sun protection clothing fits your needs, rather than the other way around. For some, that means full body cover from the waist up, and therefore a long sleeve hooded shirt is best. For others, a long sleeve shirt paired with a sun protective hat fits the bill. Or maybe you’re gearing up for a strenuous outdoor workout or stepping out into extremely hot weather. In either case, a short sleeve UV shirt and proper sunscreen application could be the most appropriate. Just as with the design, the fabric must also be versatile enough to handle whatever life brings, from a hot day at the beach or a long fishing trip, to a run in the rain or a hike through multiple climate zones. This is where the perfect blend of fabrics, including viscose from bamboo, balances lightweight, quick-drying breathability and broad spectrum UV protection. Ultimately, the best shirts with UV protection need the versatility to meet your lifestyle.

Durable, Long-lasting UV Protection

What good is UV protection if it doesn’t last as long as you need it? The best sun protection clothing is built to last, both in terms of UV protection and general apparel construction. Rayward Apparel’s design team goes to great lengths to find fabric blends that resist pilling. As a result, your shirts look great wash after wash. Plus, our Sun Bound shirts with UV protection are made to stretch and withstand the abuse of a wide range of activities, both wet and dry, hot or cold.

Hiking mountains on a sunny day

Broad Spectrum UV Protection

Ultimately, the best sun protection clothing needs to effectively protect you from the sun’s damaging UV rays, both UVA and UVB. This means dependable broad spectrum protection when and where you need it most. Unlike typical lightweight clothing, UPF 50+ apparel blocks over 98% of the harmful UV radiation that would otherwise cause sunburns, or worse. To find the best sun protection clothing, look for product labels that indicate a UPF rating of 50+, the fabric equivalent of SPF 50, and the highest possible UV protection.

Shirts with UV protection that meet the criteria outlined above, like Rayward Apparel’s Sun Bound shirts, are your best option for high performance sun protective clothing. Not only do our Sun Bound UPF shirts look great, fit comfortably and hold up to the demands of an active lifestyle, they meet the highest standards of UPF protection, rated at UPF 50+. To learn more and shop our Sun Bound UPF 50+ shirts, CLICK HERE.

Does UPF Wash Out Of Clothing?

Will UPF wash out? Washing Machines.

So you’ve gone ahead and bought some UPF 50+ clothing, but what happens when it goes through the wash? Will any of that sun protection value be ‘washed out’ or will it keep protecting you at the same level? 

Depends On How The UPF Value Was Initially Achieved

The two most popular ways different apparel companies achieve a UPF rating are through 1) Properly constructing and designing a shirt with sun protection in mind and 2) Using a chemical on the clothing or threads with a chemical to boost it’s UPF rating. At Rayward Apparel we always recommend the first, the chemical free option, as it is not something that can ever ‘wash out’.


The fabric design and composition plays a big part in the UPF rating. Some of these factors include the shirt weight, fabric blend, color, fit, and more. But ultimately, you want to make sure you are buying a product that has achieved it’s UPF value through these means, versus using chemical coatings to achieve it’s rating. If designed correctly, UPF 50+ clothing will always maintain that value and will not wash out of the product.


Gas Mask, Chemicals Impacting UPF

There are a variety of different chemical and oil infusions that can help boost a fiber’s UPF value. At Rayward Apparel, we generally disagree with this strategy as we think it opens a whole new set of potential issues:

  • Bad for the environment
  • Depending on the chemical, it’s possible it washes out of the fibers
  • Introduces more possibility for allergic reactions depending on the individual wearing it

Product Quality

As mentioned above, a lot of factors go into the design of a sun protective shirt to ensure it keeps you protected from harmful UV rays. Some of these factors include the shirt weight, fabric composition, color, fit, and more. But at the end of the day, the quality of the shirt plays a big part in maintaining its UPF rating – especially if it’s being worn and washed often. 

As your clothing starts to age it naturally becomes a little worn down. So you may not be ‘washing out’ the sun protection rating of your UPF 50+ clothing, but it’s possible the rating drops as  the shirt ages. This is especially true with a low quality shirt.  Depending on the durability of your clothing the fabric composition may be compromised after only a couple washes. In other words, as the threads thin out it allows more UV light to pass through. So while the UPF does not necessarily wash out, if you have a low quality shirt the UPF protection rating will start to drop over time. Higher quality shirts and more durable construction are designed to withstand the harshest environments and maintain a UPF rating for the life of the shirt – as is the case with all Rayward Apparel products. 

Simple Recommendations to keep your UPF 50+ clothing lasting as long as possible:

Clothes Line with UPF 50+ Clothing
  • Don’t wring out your sun protection clothing, this can permanently stretch the fibers which can lower the UPF rating.
  • Do not bleach. Even you are bleaching a white shirt and won’t cause any discoloration, it’s possible it damages the fibers. Bleach is great, however it’s a fairly harsh chemical on clothing. It’s best to keep your UV protective shirts intact. 
  • Wash your clothing in cold water. Warm and hot water is more likely to shrink your fabric which could in turn shorten the lifespan of the UPF clothing.

To learn more about our apparel and to view our current line of UPF 50+ clothing, check out our shop!

What Does UPF 50 Mean?

Sailboat on sunny day

UPF stands for Ultraviolet Protection Factor – it’s the standard used to measure the amount of UV protection a fabric provides. The higher the UPF factor the better. UPF 50 is the highest possible rating for sun protective clothing, but what does it really mean?

Blocks 98% of all UV rays

The number 50 represents the factor to which the clothing protects the skin. When something is labeled as UPF 50 clothing, that means it provides excellent protection against harmful UV rays. For instance, a UPF 50 product allows only 1/50th of the harmful rays to penetrate the fabric. 

Sunscreen vs UPF 50

The sun emits two types of damaging UV rays – long wave ultraviolet A (UVA) and short wave ultraviolet B (UVB). It’s important to protect your skin from both. One of the key differences between UPF and SPF is that all sun protective fabrics (UPF) protect your skin from both types of radiation. Sunscreen (SPF) on the other hand only shows it’s effectiveness in protecting your skin from UVB rays. Always make sure your buying “broad-spectrum” sunscreen which protects you from both. 

We often get asked if sun protective clothing is a better option than sunscreen. Our answer – yes and no. You can’t really have one without the other. UPF 50 clothing does not ever require re-application is an excellent way to ensure you are protected from the sun, but it only protects the covered areas of your skin. In addition, even with the best apparel it’s important you also have a high quality sunscreen. Clothing can only cover so much, you still need to protect your face, neck, and other areas that are exposed to the sun.

‘Excellent’ Protection According to Standard Testing

All fabrics that list a UPF value must be tested according to the ASTM standards. The test measures UV penetration of a fabric and determines its exact UPF value, but sometimes this value is not always listed. Along with a UPF rating, the test results show the official Protection Category the fabric falls into. UPF 50 clothing falls into the ‘Excellent’ protection category – the best possible category. Fabrics with a UPF rating of 25 – 39 have ‘Very Good’ protection, and fabrics with a UPF rating of 15 – 25 have ‘Good’ protection. Anything less than UPF 15 is not considered a protective fabric. In summary, if you’re going to be out in the sun, make sure you are protected.

How Do I Know The UPF Value Of My Clothing?

All fabrics have some UPF rating, but it’s close to impossible to determine without proper testing. If a product has been tested and is designed for sun protection look for it’s UPF rating. First, just look on the tag and see if it’s listed there. If not, you might be able to find it through a quick google search. If it’s not listed anywhere on the product or in the product details, it’s likely never been tested. With any Rayward Apparel, you can have the piece of mind knowing ALL of our products achieve a UPF rating of 50 or more. 

Side by side, UPF 50 clothing may look and feel the same as all of the other options, but don’t be fooled. A common misconception is that any t-shirt will keep you properly protected from the sun – which is far from the truth. The average t-shirt has a UPF value of 1-4, providing minimal protection from UV rays. UPF clothing really does work and a ‘must-have’ for anyone that loves the outdoors. In the short video below to the right, a dermatologist from the Mayo Clinic provides some more insight:

Does All Clothing Have UPF?

Variety of Clothes, do they have UPF?

UPF stands for Ultraviolet Protection Factor, the degree to which a fabric protects you from UV rays. All fabrics have some level of protection, but without proper testing it’s impossible to know the exact UPF rating. Continue reading to learn the role of UPF ratings in UV protective clothing.

How Do I Know If My Shirt Has a UPF Rating?

Generally speaking, if a fabric has been tested to determine it’s UPF rating you will see it somewhere on the fabric itself. It may be fused onto the inside of the shirt, or on the tag. In addition, you can also quickly look it up online to see if the UPF rating is listed in the description. If you’ve checked all of those areas and still cannot find the UPF rating, it’s likely it was never tested. While most UV protective clothing goes through the extra steps of verifying it’s rating, it’s a costly process. Most clothing without UV protection in mind will not have the fabric lab tested, and thus will not have an official UPF rating.

What Is the UPF of a Cotton Shirt?

As mentioned previously, without proper testing it’s impossible to provide an exact number. There are a lot of different factors that impact a shirts UPF rating, so every shirt is different. However, a good rule of thumb for a fairly standard cotton shirt is to assume a UPF rating of about 5. UV protective clothing has a minimum rating of UPF 15, so 5 is far below anything professionals would consider ‘protective’. The following video provides a great summary of the difference a UPF rated shirt can provide versus your standard cotton shirt:

What Is Considered a Good UPF Rating for UV Protective Clothing?

The ASTM (American Society for Testing and Materials) sets the standard for the different UPF ratings in the United States. They published the below chart, which determines the ‘protection category’ of different fabrics based on the UPF rating:

UPF RatingProtection Category% UV Radiation Blocked
UPF 15 – 24Good93.3 – 95.9
UPF 25 – 39Very Good96.0 – 97.4
UPF 40 – 50+Excellent97.5 – 98+

In summary, anything below UPF 15 does not even receive a protection category and is not considered UV protective clothing. At Rayward Apparel, we only sell apparel that has a UPF 50 rating or better, ensuring our customers are properly protected. 

You may be more familiar with SPF, as it’s the rating given to sunscreens. As far as the actual rating number is concerned, they represent the same level of protection. So a UPF shirt provides the same degree of protection as an SPF sunscreen, but there are some differences which you need to be aware of:

Is UPF The Same As SPF?

Umbrellas, UPF vs SPF

UPF is the rating given to fabrics, whereas SPF is the rating given to different sunscreens. The number itself is the same, it determines the protection factor in which it blocks UV rays. However, there is one major difference which is important to keep in mind: UPF is inherently broad-spectrum – it blocks both UVA and UVB rays. SPF on the other hand, only rates it’s effectiveness against UVA rays. So when buying UV protective clothing, no need to check for a “broad-spectrum” statement. But, when you are buying sunscreen make sure it’s labeled as “broad-spectrum” so you get full protection. Both UVA and UVB rays are linked to skin cancer, so you should definitely be protecting yourself from both.

What is the Difference Between UPF and SPF?

Kayaking at Sunset with UPF Protection

You’re probably familiar with the SPF (sun protection factor) ratings found on sunscreen, but what is UPF clothing? Did you know clothing has its own UV protection rating system? You’ll see this rating, known as an ultraviolet protection factor, or UPF for short, when buying sun protective clothing or bamboo apparel. But what exactly do SPF and UPF ratings measure, and how do they compare?

Before we dive into the differences, it’s important to understand the reason we are protecting our skin at all. The ultraviolet (UV) rays from the sun are harmful, especially during long periods of exposure. Unprotected exposure to UV rays damages the skin, and cause over 90% of all nonmelanoma skin cancers.

Sunny blue sky with UV rays


Sunscreen labeled as “broad-spectrum” blocks both UVA (long wave ultraviolet A) and UVB (short wave ultraviolet B), each of which damages the skin. Any sunscreen not labeled broad-spectrum is generally designed simply to protect from short wave UVB rays to avoid a burn, but will not block harmful UVA rays. Whenever possible, always choose broad-spectrum protection.


SPF stands for “sun protection factor” and is a relative measure of a sunscreen’s effectiveness in protecting your skin from UV rays. A higher SPF rating means that it will block a higher percentage of UV rays, but nothing is 100%. The number generally correlates to the multiple of time in which you can avoid a burn. So if you would normally burn in 10 minutes, and properly applied an SPF 30 sunscreen, it would take you about 300 (10 x 30) minutes to burn (assuming you are constantly covered and re-applying).


So we know what Broad-Spectrum and SPF are, but what is UPF clothing? UPF (ultraviolet protection factor), on the other hand, is specific to sun protective fabrics. UV radiation can penetrate clothing and as with SPF, the higher the value, the more protection you receive. The specific UPF rating of the garment indicates the amount of the sun’s UV radiation it allows through. For example, a UPF 50 shirt only allows 1/50th or 2% of the UV rays through, a UPF 30 shirt only allows 1/30th or about 3% through, and so on. Plus, unlike sunscreen, UPF apparel always blocks both UVA and UVB rays and is always broad-spectrum.

UPF ratings can be difficult to identify, as they’re rarely marked in any product details. That is, unless the garment is specifically designed for UV protection. The average cotton t-shirt’s UPF value is 5 or less, and determining the exact UPF rating requires costly, time-consuming testing. Also, while it’s required that apparel show its country of origin and fabric content, there is no requirement for a manufacturer to provide the product’s UPF rating. This leads to many companies taking the cheap and easy route—not listing it at all. So in general, if an article of clothing does not have a UPF value listed (and it’s not thick like denim or heavy fleece), it’s safest to assume it does not provide significant UV protection.

Kayaking at Sunset with UPF Protection

SPF & UPF, In Summary:

  • SPF rates the UV protection effectiveness of sunscreens
  • UPF rates the UV protection effectiveness of protective fabrics
  • UPF is always broad-spectrum, SPF is not
  • Fabrics with UPF provide constant coverage, SPF and sunscreens need regular re-application to maintain protection
  • When choosing UPF apparel, look for ratings of UPF 50+ for the best protection

Rayward Apparel focuses exclusively on UPF 50+ apparel, specializing in sun protective shirts that are as comfortable as they are protective. Shop Rayward Apparel today!

Our vision sees through the sun’s glare and extends far beyond clothing. We go beyond clothing with our dedication to supporting the fight against skin cancer, donating 5% of all profits to charities with a similar vision to ours. Learn more about how we give back.

Source: Skin Cancer FoundationSkincancer.org


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