SPF and broad spectrum on a sunscreen label
The FDA says SPF indicates the level of sunburn protection, which is mostly UVB, and broad spectrum means protection against both UVA and UVB. The AAD recommends a sunscreen with a label that says broad spectrum, SPF 30 or higher and water resistant. The FDA’s own tip names SPF 15 or higher.
Two phrases on a sunscreen label do most of the work: SPF and broad spectrum. This page explains them using the FDA and the American Academy of Dermatology (AAD).
What SPF measures
The FDA says the sun protection factor (SPF) value indicates the level of sunburn protection a sunscreen provides. Every sunscreen is tested to measure how much UV radiation exposure it takes to cause sunburn with the product, compared with without it. The FDA says higher SPF values, up to 50, provide greater sunburn protection.
Because the test measures sunburn, the FDA says SPF values mainly indicate UVB protection. It also says SPF is not about time. SPF 15 does not mean 15 times longer in the sun, because SPF relates to the amount of solar exposure, not the minutes.
DermNet gives approximate figures for UVB: SPF 15 about 94 percent, SPF 30 about 97 percent and SPF 50+ about 98 percent.
What broad spectrum means
The FDA says broad spectrum sunscreens help protect against both UVA and UVB. It says not all sunscreens are broad spectrum, so look for the description on the label.
The FDA says sunscreens that are not broad spectrum, or that have an SPF below 15, must carry a Skin Cancer/Skin Aging Alert on the Drug Facts label. The alert says the product has been shown only to help with sunburn, not with skin cancer or early skin aging.
The Drug Facts label
In the United States, sunscreens are regulated as drugs, and the FDA says their labels use the Drug Facts format. The FDA says Drug Facts labels list the same sections in the same order: active ingredients, purpose, uses, warnings, directions and inactive ingredients.
What the AAD recommends
The AAD says to select a sunscreen whose label says:
- Broad spectrum, meaning protection from both UVA and UVB rays.
- SPF 30 or higher.
- Water resistant, which the AAD says lasts either 40 or 80 minutes.
The FDA’s tips are worded a little differently. It says to use broad spectrum sunscreens with an SPF of 15 or higher regularly and as directed. These are two sources with two thresholds, so this page gives both.
Water resistant is not waterproof
The FDA says there is no such thing as waterproof sunscreen and that all sunscreens eventually wash off. Products labeled water resistant must state whether protection lasts 40 or 80 minutes when swimming or sweating.
How much, and when
- The FDA and the AAD both say to apply sunscreen about 15 minutes before going outside.
- The AAD says most adults need about 1 ounce, roughly a shot glass, for skin not covered by clothing, and at least 1 teaspoon for the face.
- Both say to reapply at least every two hours, and more often after swimming or sweating.
- The FDA says sunscreen is not recommended for infants under six months and to ask a doctor before using it on them.
- The FDA says sunscreen should be used with other sun protection measures such as clothing and shade.
What Poliage shows
Poliage reads the ingredient list. A product page says Contains and then an ingredient and its function, for example a UV filter. SPF and broad spectrum claims are on the pack’s Drug Facts or front label, and the label on the pack comes first. Poliage gives product information, not medical advice.
Where this comes from
SPF, broad spectrum, water resistance and the Drug Facts label come from FDA consumer pages. The recommendation for SPF 30 or higher, broad spectrum and water resistant comes from the AAD pages on how to select and how to apply sunscreen. The percentages come from the DermNet NZ page on topical sunscreen agents. All were read on 2026-10-22.