What Are SPF and PA? How to Read a Sunscreen Label Before You Wear It Every Day
If you’ve ever picked up a sunscreen and felt the numbers and symbols on the label were just too hard to read, you’re not alone. Is “SPF50+ PA++++” a “good” sunscreen? Why do some have just one + and others four? And is a higher SPF number always better?
These questions sound simple, but most people still can’t answer them clearly. This article explains them properly, from the ground up, in language you can follow even without a science background.
What Is SPF?
SPF stands for Sun Protection Factor. It’s the number that tells you how much a sunscreen protects against UVB.
UVB is the radiation that burns and reddens skin and leaves it feeling sore after a long time outdoors. An easy way to remember it: B for Burning.
The SPF number tells you how many times longer your skin can “tolerate the sun” compared to wearing no sunscreen. For example, if your skin normally starts to redden after 10 minutes outdoors, wearing SPF30 means it will start to redden about 30 times more slowly.
How to Read the SPF Value on a Label
Today, international standards state that if the tested SPF is higher than 50, the manufacturer displays it on the label as “SPF50+” instead of the real number. That means a sunscreen labeled SPF50+ may have a real value much higher than 50, depending on each brand’s formula.
What Is PA? What Does PA Stand For?
PA stands for Protection Grade of UVA. It’s the indicator that shows the level of protection against UVA, which is a different type of radiation from UVB.
UVA is easy to remember as A for Aging, because it’s the radiation that ages skin prematurely, forms fine lines, dark spots, and dullness without your feeling the sting of sunburn the way UVB does. UVA also penetrates clouds and glass, so you can still be exposed even in the shade or inside a car.
PA Has 4 Levels — More Pluses, Higher Protection
The PA value is derived from a number called UVA-PF (or PFA) and is shown as plus symbols on the label, as follows:
| Level | UVA-PF | Protection Capability |
|---|---|---|
| PA+ | 2 – 4 | Some protection |
| PA++ | 4 – 8 | Moderate protection |
| PA+++ | 8 – 16 | High protection |
| PA++++ | 16 and above | Very high protection (highest) |
A sunscreen with PA++++ is the highest level in the current standard, and the most suitable for anyone who wants serious UVA protection.
How Do SPF and PA Differ? Which Should You Check First?
Many people mistakenly think a high SPF is enough, but the truth is that SPF protects only against UVB. It can’t protect against UVA at all without a PA value alongside it.
| SPF | PA | |
|---|---|---|
| Protects from | UVB (burning, redness) | UVA (premature-looking aging, dark spots) |
| Measured by | Sun Protection Factor | UVA-PF (Protection Factor of UVA) |
| Shown on label | A number, e.g. SPF30, SPF50+ | Plus symbols, e.g. PA++, PA++++ |
| UV range | 290–320 nanometers | 320–400 nanometers |
A simple comparison: if sunscreen were a hat and an umbrella, SPF is the hat that protects against sunburn, while PA is the umbrella that protects against aging. Walk into the sun without the umbrella, even wearing the hat, and your skin can still deteriorate from UVA.
Why You Should Always Check Both SPF and PA — How to Choose a Sunscreen
Our skin is hit by both UVB and UVA at the same time every time we’re in the sun. So a good sunscreen has to protect against both.
What to look for when choosing a sunscreen for everyday use:
- SPF of at least 30 for indoor use, or SPF50+ if you’re out in the sun for long periods
- PA++++ or PA+++ to protect against the UVA that ages skin prematurely
- Reapply every 2-3 hours, whether or not the sunscreen says it’s water-resistant, because the protective film degrades over time, with sweat, and with contact
For people living in the city, UVA is more of a concern than you might think, because it penetrates car windows, building glass, and clouds — so your skin is exposed to UVA even on overcast days or while working in a room with natural light.
A Real Case from the Lab — Why Honest Numbers Matter
CMe Ultra-Light Refreshing Facial Sunscreen SPF50+ PA++++ passed in-vivo testing under the international standard ISO 24444 at Solar Test Asia, with the following real results:
- Real SPF: 65.8
- Real UVA-PF: 24.7 (equivalent to PA++++, which requires a minimum of 16)
But on the product label, CMe chooses to claim only “SPF50+” — not SPF65 or SPF70.
Why choose it this way?
Because international standards already call for rounding any SPF above 50 down to “50+” on the label, and CMe believes that displaying exaggerated numbers doesn’t give you better protection. What matters instead is knowing that the sunscreen you’re using has passed testing at a standard lab with verifiable numbers.
In addition, CMe Ultra-Light Refreshing Facial Sunscreen was tested at M.C.I.I = 0.07 (below 0.2 is considered gentle), making it suitable even for sensitive skin.
More worth knowing:
- An 8-Free formula, free of Alcohol, Fragrance, Paraben, Colorant, Mineral Oil, Silicone, Steroid, and Formaldehyde
- A light Soft-Matte texture that absorbs quickly and leaves no white cast, ideal for reapplying during the day without feeling heavy
- Water Resistance of 40 minutes, holds up well to sweat, but reapply if exposed to water or heavy sweating — it’s not a one-and-done for the whole day
- Thai FDA notification no. 13-1-6800042825
You can see more details on the formula and test results on the CMe sunscreen product page.
Where Honest Numbers Came From — Cheer, Founder
CMe’s Honest Numbers philosophy didn’t come out of nowhere. It traces back to a night when founder Cheer washed her face three times with foam, believing more washing meant cleaner skin — she woke up to badly damaged, irritated skin despite her best intentions. A dermatologist explained the real problem was a misunderstanding of numbers, not a lack of care. That experience is why Cheer insists every number CMe tells a customer has to be verifiable, never rounded up to sound better — the same reason CMe claims only SPF50+ on the label, even though real testing showed 65.8. Read Cheer’s full story ›
Summary: Read Your Sunscreen in Full, Not Just the Number
A good sunscreen isn’t measured by a high or low SPF number alone — you need to consider both values together.
- SPF protects against UVB — the radiation that burns skin
- PA protects against UVA — the radiation that ages skin prematurely and dulls it
- PA++++ is the highest level of UVA protection
- Always reapply, no matter how “water-resistant” it is
Next time, before you reach for a sunscreen, check both the SPF and the PA first — and you’ll be able to choose what your skin truly needs.
Frequently Asked Questions
What is PA++++ and how is it different from PA+++?
PA++++ is the highest level of UVA protection, UVA being the rays that cause premature-looking aging, fine lines, and dark spots. PA++++ means a UVA-PF of 16 or higher, while PA+++ sits at 8-16. If you want the highest possible UVA protection, PA++++ is the better choice.
Is SPF50+ enough for everyday use?
SPF50+ protects against UVB very well for daily life, but you should look at the PA value alongside it. SPF only covers UVB (sunburn), while UVA (premature-looking aging) needs the PA value to guard against it. Choosing a sunscreen with both SPF50+ and PA++++ gives you complete protection against both types.
What's the difference between SPF and PA?
SPF measures protection against UVB, the rays that burn and redden skin. PA measures protection against UVA, the rays that cause premature-looking aging, fine lines, and dark spots. The two types affect skin differently, so you should always use SPF and PA together.
What are the real SPF and PA values of CMe sunscreen?
CMe Ultra-Light Refreshing Facial Sunscreen was tested in-vivo and achieved a real SPF of 65.8 and a UVA-PF of 24.7 (equivalent to PA++++) under the ISO 24444 standard at Solar Test Asia. But CMe chooses to claim only SPF50+, following our Honest Numbers principle of never inflating the figures.
If a sunscreen is water-resistant, can one application last all day?
It shouldn't. Even though CMe sunscreen passes a 40-minute Water Resistance test, you still need to reapply every 2-3 hours, or after heavy sweating, contact with water, or wiping your face, because the protective film degrades over time.