⬆️ How do upgrades and contracts work?

The Trade Up Contract in the real game

In CS2's Trade Up Contract you give 10 skins of the same rarity and get 1 skin of the next rarity. The result comes from the collections of the skins you put in, and its wear depends on the average float of your inputs. Since the October 2025 update, 5 Covert skins can also be traded up into a knife or gloves.

Contracts on KasaSim

On KasaSim the contract is simpler: you give 5 skins of the same rarity and get 1 skin of the next one (Mil-Spec → Restricted → Classified → Covert). The result is picked at random from items priced close to the total value of your 5 skins, roughly between 0.6 and 2.2 times that total. Knives and gloves can't be used.

The nice thing about contracts is that the result always comes from the next tier up. Instead of selling the cheap Mil-Spec skins you collect from cases, putting them into contracts is a good way to fill the Restricted and Classified gaps in your collection.

Upgrades: risk and chance

In an upgrade you try to swap one of your skins for a more valuable target. Success chance = (your skin ÷ target price) × 0.9, kept between 2% and 90%. A $50 skin against a $100 target gives 45%, against a $500 target 9%. Win and you get the target; lose and your skin is gone.

Because of the 0.9 factor, the average return of an upgrade is 90% of what you put in. Someone who does many upgrades loses a little on average; upgrading is more about the thrill of a big item in one shot than about growing value.

Which one, and when?

If you have lots of cheap skins of the same rarity, a contract is the safer choice. If you want to gamble one mid-value skin on a big target, the upgrader is more exciting. In both, the server decides the result and the odds are the same on every try.