Float capping is how experienced traders control the wear of a trade-up output. Valve has not published the formula, but community testing shows the game does not simply average the input floats. Each input float is placed inside that input skin's own cap, the ten positions are averaged, and that average is mapped onto the output skin's cap. Because many output skins have a maximum float well below 1.00, the mapped result is often cleaner than the inputs.
The goal is to sit just under a tier boundary such as 0.07 for Factory New or 0.15 for Minimal Wear. Inputs that are cleaner than needed cost more and add nothing to the price of the output, so the cheapest winning contract uses inputs that are exactly as clean as they need to be.
How do you float cap a trade-up?
Start from the output. Pick the target skin, note its float cap, and decide which wear tier you want. Work backwards to the highest average normalized float that still lands in that tier. Then shop for inputs whose floats keep the average under that line. Cheaper, higher-float inputs are fine as long as the mapped average stays in range.
A float cap calculator does this arithmetic for you. Enter the input floats and the output cap, and it shows the exact output float. Check it before the contract, since a single high-float input can push the result across a tier line and cut the value of the outcome.
What are the common mistakes in float capping?
The first is mixing collections with very different outputs and forgetting that the float math applies to whichever skin the contract picks, and each possible output has its own cap. A set of inputs that caps nicely for one output may land in Field-Tested for another. The second is trusting the wear label of inputs instead of their exact floats. Two Field-Tested inputs at 0.16 and 0.37 do very different things to the average.
The third is ignoring StatTrak and Souvenir rules. Steam Support says StatTrak inputs cannot mix with normal ones, and since the 22 May 2026 update Souvenir inputs can be mixed with normal ones but lose their Souvenir attributes, with the output always a normal item. Float capping only pays off when the rest of the contract is set up correctly.