SPF is the rating on your sunscreen. UPF is the rating on your fabric. They measure different things, they're tested in different ways. If you've ever stood in a shop wondering whether a UPF 50+ shirt is the same as SPF 50 sunscreen, the short answer is no, and the longer answer is worth two minutes.
Cancer Council SunSmart puts it plainly: in Australia we get some of the harshest UV in the world. Their advice is to cover up whenever the UV Index reaches 3 or above. That's the backdrop for every number below.
What is the difference between UPF and SPF?
UPF rates how much UV a fabric lets through to your skin. SPF rates how well a sunscreen protects your skin from sunburn. One is a property of a material. The other depends on how much you put on and how often you put it back on.
That second part matters more than most people think. Cancer Council recommends about one teaspoon (5mL) for each arm, each leg, the front, the back and the face including neck and ears, which comes to about seven teaspoons (35mL) for an adult, reapplied at least every two hours. A fabric needs none of that. Once it's on, it's on, and it covers evenly.
Sun protective clothing is rated under AS/NZS 4399, the Australian and New Zealand standard for sun protective clothing. Sunscreen has its own standard, and SunSmart suggests looking for AUST L or AS/NZS 2604 on the label.
What do the UPF numbers actually block?
ARPANSA, the Australian Radiation Protection and Nuclear Safety Agency, lists three classes in the current standard:
| Class | UPF rating |
|---|---|
| Minimum | 15 |
| Good | 30 |
| Excellent | 50 and 50+ |
UPF 50+ is the top class. It means one fiftieth or less of the UV reaching the fabric gets through, so the fabric blocks at least 98%. There's no UPF 100 or UPF 1000 in the Australian classes, whatever a marketplace listing tells you. A fabric with no rating at all simply hasn't been measured, and a photo won't tell you.
What makes a fabric block UV?
ARPANSA lists the things that decide how much UV gets through a fabric. None of them shows up in a photo.
- How tightly it's made. The tighter the fabric, the less space between the strands for UV to pass through. Hold a fabric up to a window: the more light you see through the gaps, the more UV is getting through as well.
- How thick it is. Thicker fabric measures higher. The catch is that heavy fabric is hard to wear all day, which is why a good sun fabric is dense in structure without being thick.
- How much it's stretched. Stretching a fabric normally lowers its UPF, because the gaps open up. That's one reason fit matters on a sleeve.
- Colour. In general, darker colours absorb more UV than lighter ones, which means less UV gets through.
- Its condition. After a lot of washing a garment can fade and wear, which can lower its UPF.
Does the colour of a sleeve change how much UV it blocks?
On fabric in general, darker colours absorb more UV so less UV hits the skin. On a UPF rated fabric it matters less, because the rating already tells you what the fabric blocks. The fabric in our white arm sleeves is also tested and achieves the same ARPANSA UPF 50+ rating. Every print is tested at the mill, and each year we send a random selection of prints for further testing.
What colour can change is whether the sleeve gets worn! A kid who picks their own print keeps it on, whether that's the dolphin kids arm sleeves or a plain colour from the kids arm sleeves range. In practice, the sleeve that gets worn is the one that protects.
Are UV sleeves better than sunscreen?
For arms, yes. They are a more flexible, convenient, and more reliable way to protect arms than applying sunscreens. A sleeve goes on once. Cancer Council's advice for sunscreen is to reapply every two hours, or after swimming or heavy sweating.
You will still need shirts, a hat, shade and sunglasses for everything they don't cover.
Do you still need sunscreen under a UPF sleeve?
No. On the arm itself, the sleeve is doing the job. However sunscreen is still important for the back of the hand, and make sure there are no gaps at the top between the arm sleeve and the shirt.
Where does a sleeve sit among the other sun protection strategies?
SunSmart lists five forms of sun protection and says to use them together whenever the UV Index is 3 or above: clothing, sunscreen, a hat, shade and sunglasses. A sleeve is clothing for the part of you that is hard to keep sunscreen on consistently, and is easy to forget about day-to-day.
SunSmart also notes that UV is highest in the middle of the day, between 10am and 2pm, or 11am and 3pm in daylight saving. That's most of a round of golf, most of an innings and most of a Saturday in the garden.
How is UPF tested?
A sample of the fabric goes into an instrument that shines UV light through it and measures how much comes out the other side, across the UVA and UVB range. That measurement becomes the UPF number. Sunscreen is tested quite differently, on people's skin, and our post on how SPF and UPF ratings are tested sets the two side by side.
The test is run on the fabric, not on the finished garment, so the rating describes the material, not the cut of the sleeve or how much of you it covers.
You can do a rough version at home. Hold the fabric up to a bright window. If you can make out the shape of your hand through it, UV is getting through too. It won't give you a number, but it tells you quickly whether a t-shirt is likely to provide any protection.
Does UPF fabric wear out?
It can. ARPANSA notes that heavy washing can fade and wear a garment and lower its UPF, and that stretching a fabric opens it up. So look after the stretch: wash cold, skip the fabric softener and bleach, don't tumble dry, and dry them outside.
Where else do you need sun protection?
A sleeve covers your arm from the upper arm to the wrist, or over the back of the hand if it has a thumbhole. It doesn't cover your face, neck and ears, which need a hat and sunscreen. It doesn't cover your shoulders if you're in a singlet, or your fingers, or the gap between the top of the sleeve and a cropped sleeve shirt.
If the answer for your day is a long sleeve shirt, wear the shirt. If it's shade and a hat, take those. Sleeves are the great roll-on roll-off option when you want your arms covered without a full sleeve shirt.
What fabric do Crazy Arms sun sleeves use?
The fabric used across Crazy Arms sun sleeves is ARPANSA tested UPF 50+, which means it blocks at least 98% of UV. It's a lightweight fabric, imported from Italy, with two way stretch so it sits like a second skin. A gentle elastic band at the top keeps the sleeve where you put it, rather than halfway down your forearm by the third hour.
The fabric is made with ECONYL® regenerated nylon: 90% ECONYL® regenerated nylon and 10% elastane. ECONYL® is a yarn regenerated from nylon waste, including ghost fishing nets recovered from the ocean.
Two honest limits. Swatches of the fabric go for testing periodically, so it's the fabric that's tested, not every sleeve in your drawer. And UPF 50+ rates the material, not how much of you is covered.
If you want to see the range, start with our arm sleeves for sun protection.
So which fabric is best for a sun sleeve?
A tightly made synthetic, light and cool enough to wear all day, stretchy enough to fit without gaping, and tested to UPF 50+ by somebody independent. If a listing can't tell you the weight, the fibre and who tested it, that's your answer.
UPF and SPF questions
Is UPF better than SPF?
Neither is better; they rate different things. UPF rates how much UV a fabric lets through. SPF rates how well a sunscreen protects skin from sunburn. A UPF 50+ sleeve and SPF 50 sunscreen do different jobs on different parts of you.
What does UPF 50+ mean?
It's the top class in the Australian and New Zealand standard for sun protective clothing, the one ARPANSA calls Excellent. It means the fabric blocks at least 98% of the UV hitting it.
Do you actually need UPF clothing?
You need cover of some kind through an Australian summer. SunSmart lists five forms of sun protection, clothing among them, and says to use them together whenever the UV Index is 3 or above. A rating tells you what the clothing is actually doing.
Should I wear sunscreen under a UPF shirt or sleeve?
No, but use sunscreen the fabric doesn't cover. Under the fabric itself, it's already doing that job. Watch the gap between the top of an arm sleeve and a cropped sleeve shirt, because that band of skin is easy to miss, and the back of the hand.
What colour shirt is best for sun protection?
On fabric in general, darker colours absorb and block more UV. On a UPF rated fabric, the rating already tells you what it blocks. Pick a colour of print you or your kids like; one that will actually get worn. With younger kids, that may mean letting them choose a fun print.
Can you get sunburnt through a sun shirt or sleeve?
Rated UPF 50+ fabric blocks at least 98% of the UV hitting it. Check the gap at the top of the arm before you go out, because that's the bit a sleeve never covers.
Is an ordinary cotton shirt enough?
It's better than bare skin, but without a rating you don't know what it lets through. Weave, thickness and colour all change how much UV a fabric blocks. A rating takes the guesswork out.