Not every CS2 skin can span the full 0.00 to 1.00 float scale. Each finish has its own float cap, a lowest and highest float that copies of the skin can be created with. Some skins run from 0.00 to 1.00, while others are capped much tighter, such as 0.00 to 0.50, 0.06 to 0.80 or 0.00 to 0.08. Valve's Weapon Finishes guide says each paint specifies a range for wear and a random value is chosen within that range when the item is made. The cap is part of the skin's definition in the game files and is the same for every copy; the ByMykel item dataset lists the minimum and maximum for every skin.
The cap explains why some skins never appear in some wear tiers. A skin with a minimum float of 0.18 cannot be Factory New or Minimal Wear, and a skin with a maximum float of 0.40 cannot be Battle-Scarred.
How does the float cap change what a good float looks like?
A float is only rare relative to the cap. For a skin capped at 0.00 to 1.00, a 0.02 float is clean but not unusual. For a skin whose minimum is 0.06, a 0.065 float is close to the best possible copy and can command a premium even though it barely qualifies as Factory New. The same logic works at the top end, where the highest possible float for a capped skin becomes a collector item.
When you compare prices, check the cap first. Price sites and float checkers usually show the range next to the float, so you can tell whether a listing is special or ordinary.
Why is the float cap central to trade-ups?
Valve has not published the output float formula, but community testing shows the output is not a plain average of the inputs. Each input float is first placed inside its own cap, those positions are averaged, and the average is mapped onto the output skin's cap. If the output cap is narrow, the result lands in a tighter, often better wear tier than the inputs suggest. This is why traders can feed Field-Tested inputs into a contract and receive a Minimal Wear output, a technique called float capping.
A float cap calculator takes the input floats and the output cap and shows the exact float the contract will produce, so you know the wear tier before you commit the items.