WASHINGTON — Help is on the way if you’re confused by the maze of sun protection numbers and other claims on sunscreens.

Starting next summer, you can start looking for SPF 15 bottles and tubes with the label “broad spectrum” and feel confident they’re lowering your risk of skin cancer.

Under new rules published Tuesday, sunscreens will have to filter out the most dangerous type of radiation to claim they protect against skin cancer and premature aging. “Broad spectrum” is the new buzzword from the Food and Drug Administration to describe a product that does an acceptable job blocking both ultraviolet B rays and ultraviolet A rays.

If a sunscreen doesn’t protect against both, or the sun protection factor is below 15, then it has to carry a warning: “This product has been shown only to help prevent sunburn, not skin cancer or early skin aging.”

The guidelines, which spent more than 30 years in bureaucratic limbo, are designed to help consumers like Paul Woodburn, who says he’s not sure of the difference between UVA and UVB rays and that he judges sunscreen by one factor alone.

“The SPF number is what counts for me,” the 55-year-old Indianapolis resident said as he sat next to a public pool. “Beyond the SPF, I don’t think anybody really watches.”

The new regulations require that sunscreens be tested for the ability to block the more dangerous UVA rays, which can penetrate glass and pose the greatest risk of skin cancer and wrinkles. The FDA currently requires testing only for protection against UVB rays, which primarily cause sunburn but can also cause cancer and other damage. That’s what the familiar SPF measure is based on.

Under the new rules the FDA will:

Prohibit sunscreen marketing claims like “waterproof” and “sweatproof,” which the agency said “are exaggerations of performance.” Water-resistance claims will be allowed.

Cap the highest SPF value at 50, unless companies can provide results of further testing that support a higher number.

Require that manufacturers phase out a four-star system currently used by some companies to rate UVA protection.

SPF measures the amount of sun exposure needed to cause sunburn on UV-protected skin versus unprotected skin. The level of exposure varies by geography, time of day and skin complexion.

There is a popular misconception that SPF relates to time of solar exposure. Many consumers believe that if they normally get sunburn in one hour, then an SPF 15 sunscreen allows them to stay in the sun for 15 hours without burning. This isn’t true because SPF is not directly related to length of sun exposure.