How CS2 Trade-Ups Work
A trade-up contract turns ten skins of one rarity into a single skin one tier higher. Here is exactly how the contract decides what you get.
The 10-input rule
Every trade-up contract takes exactly ten skins as inputs, and all ten must share the same rarity. You cannot mix a Mil-Spec with a Restricted, and you cannot use nine or eleven. In return, the contract produces one skin from the rarity directly above the inputs.
The rarity tiers
Normal weapon skins climb through these tiers, lowest to highest:
- Consumer Grade
- Industrial Grade
- Mil-Spec
- Restricted
- Classified
- Covert
Trade up ten Mil-Spec skins and you receive a Restricted; ten Classified inputs return a Covert. Covert is the ceiling for standard skins, so there is no trade-up beyond it. Knives and gloves sit outside this system entirely.
How the output collection is chosen
The contract first picks which input decides the result. Each of your ten inputs effectively buys one entry into the draw, so a collection that supplies more inputs is more likely to be chosen. The output is then a random skin from that collection's next tier up. If all ten inputs come from one collection, the result is guaranteed to come from that collection's higher tier.
Working out the odds
- Per-collection odds are simply the number of inputs you supplied from that collection divided by ten.
- Per-skin odds spread that figure evenly across every possible outcome skin in the chosen collection's next tier — each candidate is generally treated as equally likely.
So a collection contributing four of your ten inputs gives a 40% chance the result comes from it; if that tier holds five possible skins, each lands at roughly 8%. Community price databases often estimate the value of these pools, but those figures shift constantly, so treat any single number as an estimate rather than a fixed fact.
Plug your own split into the CS2 trade-up calculator to see the odds update live, or read up on how float decides your output wear.