Trade-Up Contracts Explained

A Trade-Up contract converts ten skins of the same rarity into one skin of the next rarity up. It is the only mechanism in Counter-Strike that reliably moves items upward through the rarity ladder, and it is entirely deterministic in its rules even though the outcome is random.

How the outcome pool is built

The contract does not draw from every skin in the game. Each input item belongs to a collection, and each collection contributes its own next-tier skins to the outcome pool. A collection that supplies more of your ten inputs is proportionally more likely to supply the result. This is why experienced players deliberately stack inputs from a single collection: it concentrates the odds onto the specific outcome they want.

How the output float is calculated

Each input float is first normalized within that skin’s own minimum and maximum. The average normalized value is then mapped into the output skin’s range. For example, an input at 0.40 in a 0.10–0.70 range has position 0.50. An output limited to 0.00–0.80 is then 0.40. Calculations retain precision until display; prices follow wear bands rather than individual float premiums.

Reading the profitability panel

As you add items, the panel on the right lists every possible outcome with its individual probability, along with the total input cost, the expected value of the contract and the resulting profit or loss. A contract with an expected value below its input cost is a losing contract on average, no matter how good the best-case outcome looks.

Five-item Covert contracts

Valve added five-item Covert contracts in its 22 October 2025 update. Five regular Covert inputs can produce a regular knife or gloves associated with their input collections; five StatTrak inputs produce StatTrak knives. This tool builds those pools from the input cases. It does not draw from unrelated cases. Inputs without a supported output route are excluded. Probabilities model equal shares within the available pool and do not distinguish rare pattern premiums.

Price sources and limits

Price data uses Skinport suggested USD values where available and a Steam snapshot for coverage. The source date matters more than the download date. Old Steam data is not used to recalibrate fresh Skinport prices. Missing, old and modelled values are marked in the contract summary; an approximate value is not an executable quote. Edit input and outcome prices to compare your own market. Profit excludes selling fees, sticker premiums and individual float or pattern premiums.