Reviewed October 25, 2026
PA Ratings and PPD: The UVA Numbers Next to Your SPF, Explained
SPF measures mostly UVB. The PA system and PPD numbers describe UVA protection, the rays behind tanning and much photoaging. What the plus signs mean and when to care.
SPF only tells half the story
SPF is built on sunburn, and sunburn is driven mainly by UVB rays. That makes SPF a UVB score with a little UVA mixed in, not a full spectrum verdict. UVA rays penetrate deeper, run all day at steadier strength, pass through window glass, and drive tanning and a large share of visible photoaging. A sunscreen can post a heroic SPF while offering ordinary UVA protection, and the label will not volunteer the difference.
That gap is why other rating systems exist. Shoppers who care about pigmentation, melasma, and long term aging are really asking about UVA, and they need the other number, the one many labels print smaller or not at all. Learning to read it takes two minutes and changes how you shop for sunscreen permanently.
The PA system: plus signs with a meaning
The PA system, developed in Japan and used across much of Asia, grades UVA protection from PA+ to PA++++. It is derived from PPD testing, which measures how much UVA exposure protected skin tolerates compared with unprotected skin before a tanning response appears. More plus signs mean a higher PPD range and stronger UVA protection.
As a rough map, PA+ corresponds to a PPD of 2 to under 4, PA++ to 4 to under 8, PA+++ to 8 to under 16, and PA++++ to 16 and above. For daily incidental exposure, PA++ is a reasonable floor. For long outdoor days, high UV climates, or pigmentation prone skin, PA+++ or PA++++ is the sensible target, paired with an SPF of at least 30.
What other labels are telling you
Different markets signal UVA protection differently, and the patchwork confuses everyone. In Europe, a circled UVA logo means the UVA protection is at least one third of the SPF, a meaningful ratio standard. In the United States, broad spectrum is the key phrase, and it certifies that a product passes a UVA breadth test, though it does not grade how strong the UVA protection is, which is why two American broad spectrum products can differ a lot in practice.
The practical takeaway is to stack signals. Broad spectrum or the circled UVA mark tells you UVA was considered. A PA rating, where available, tells you how much. When neither a grade nor a mark is present and UVA matters to you, established products from markets with stronger labeling give you more information to choose with.
When UVA protection deserves priority
Pigmentation is the loudest case. Melasma and dark marks are driven substantially by UVA and even visible light, and they can darken through a high SPF, low UVA sunscreen in a way that baffles people who thought they were protected. Anyone managing pigmentation should shop UVA first and SPF second, and consider tinted products, since iron oxides add visible light defense.
Office workers are the quiet case. UVA passes ordinary window glass, so a desk by a bright window is a daily low dose exposure that adds up over years. It is not a sunburn risk and nobody should fear their desk, but for people investing in anti aging routines, morning sunscreen with real UVA protection is the step that defends the investment.
Related reading
If this topic is useful, these earlier guides go deeper on connected questions: UPF Clothing vs Sunscreen: When Fabric Beats a Bottle, Spray Sunscreen: How to Apply Enough for Real Protection, and Sunscreen Before or After Moisturizer? The Right Order.
Frequently asked questions
Is PA++++ always better than PA+++?
It indicates a higher measured UVA protection range, and for pigmentation prone skin and intense exposure that difference is worth having. For ordinary daily wear, PA+++ with a good SPF, applied in full amount and reapplied outdoors, serves most people well. Amount and reapplication still matter more than one plus sign.
Why does my sunscreen show no PA rating?
PA labeling is standard in Asian markets and voluntary elsewhere. American and many European products are not required to print it, which is why the broad spectrum phrase and the circled UVA logo carry the UVA message in those markets instead. Absence of a PA grade is a labeling difference, not proof of weak protection.
Does a high SPF guarantee good UVA protection too?
No. SPF primarily reflects UVB performance. Some high SPF products have proportionally weaker UVA protection. That imbalance is exactly what ratio rules in Europe and PA grades in Asia exist to expose. Check for a UVA signal separately instead of assuming the big number covers it.
What PPD number should I look for?
A PPD of 16 or higher, equivalent to PA++++, is strong UVA protection suited to pigmentation concerns and heavy exposure. PPD 8 to 16, the PA+++ band, is solid everyday protection. Below that, treat the product as light duty for brief incidental exposure.