A CS2 Fade is a finish that paints the weapon with a gradient, usually from yellow through pink to purple. Like every finish, its placement on the weapon is randomised within a range set by the finish, as Valve's Weapon Finishes guide explains, and that placement is recorded in the pattern index. The pattern decides how much of the purple end shows on the visible parts of the weapon.
Because the shift is visible, traders use fade percentage as a shorthand. A higher percentage means more of the rich purple and pink shows and less of the plain yellow. There is no Valve figure. The percentage comes from float tools and community tables that map pattern indexes to values for each weapon, and a full fade is the most sought-after version.
What is a good fade percentage?
The more purple that shows, the higher the percentage and usually the price. A float checker tool can read the percentage for you from an inspect link. Because different tools and tables can score the same pattern slightly differently, compare percentages from the same tool when you weigh two listings.
Each weapon model has its own scale. A 95% Fade on a knife and a 95% Fade on a pistol are measured on different geometry, so compare percentages only between the same item.
Do Fade skins have a float cap?
Yes, and it is narrow on most of them. In the item data, Fade knives and the AWP, Glock-18, M4A1-S, MAC-10 and UMP-45 Fades run from 0.00 to 0.08, so they only exist in Factory New and Minimal Wear, and the fade percentage counts for more than the float when pricing. The MP7 | Fade goes up to 0.25, the R8 Revolver | Fade to 0.40, and Specialist Gloves | Fade run from 0.06 to 0.80, so on those items a low float still adds value.
Fade is also one of the finishes where a listing photo can be taken from a flattering angle. Ask for the pattern index or check the inspect link before paying a full fade premium, since the difference between 90% and 100% can be large in cash but hard to spot in a single screenshot.