Abstract: A suntanning gauge is provided having a plurality of UV-light absorbing lenses of varying thicknesses affixed to a convenient-to-carry base. Under each lens is a fluorescent material which emits visible light when UV-light impinges upon it. The fluorescent material preferably is placed over a black background under each lens. Associated with each lens are indicia corresponding to the degree of strength of sunscreening compositions, the thinnest lens, for example, having the number 4 near it corresponding to a sun protective factor of 4, and the thickest lens having the number 30 near it corresponding to a sun protective factor of 30, and any desired combinations in between. On any given day, depending on the intensity of the sun, UV-light will penetrate none, one or more of the lenses, and, if a lens is penetrated, the flourescent material under it will glow. The highest indicia near a glowing lens will indicate what degree sun protective factor lotion to apply to avoid skin damage.