Every CS2 account has a trade up contract sitting in the inventory. It is easy to ignore because the interface is a paper form you sign with the mouse, but it is the only way to turn a pile of low tier skins into something better without touching the market. This covers the rules Valve actually documents, the restrictions that catch people out, and what the community has worked out about the float of the result.
What the contract does
The inventory description is short: in exchange for 10 items of identical quality, you receive a single item of a quality one higher, from a collection of one of the items you provided. The rarity ladder runs Industrial Grade, Mil-Spec, Restricted, Classified, Covert. Knives and gloves sit outside that ladder as special items.
For years the contract only worked inside the Arms Deal Collection. The September 19, 2013 update renamed it to Trade Up Contract and opened it to every collection, and the May 14, 2014 update allowed you to mix collections in a single trade.
The 2025 knife and glove change
Following the October 22, 2025 update, five Covert skins can be traded for one knife or one pair of gloves from a collection represented by the inputs. Five StatTrak Covert skins can produce a StatTrak knife. That five item contract is the only exception to the ten item rule.
What you cannot put in
- Covert or Contraband items in the standard ten item contract. Covert only goes into the knife contract.
- Knives and gloves. They are outcomes, not inputs.
- Souvenir and star quality items. StatTrak is the exception, but StatTrak and normal skins cannot be mixed in one contract.
- Any skin that is the highest rarity in its own collection. The Tec-9 Ossified is Mil-Spec but is the top tier of the Aztec Collection, so the contract refuses it.
- A grade from a collection that has no skin in the next tier up.
How the game picks the result
The result comes from one of the collections you used. Valve's own wording stops there. Community documentation says the weighting follows how many inputs came from each collection, so ten skins from one collection guarantees that collection, while a seven and three split gives the larger collection a correspondingly larger share of the outcome.
What determines the wear
This is the part with the most folklore attached. Liquipedia still describes the wear as randomly generated and states that the wear of the inputs does not affect the result. Community members have since published a formula that maps the average float of the inputs onto the float range of the outcome skin, and most trade up calculators are built on that method. Treat any calculator as an estimate rather than a guarantee, because the two descriptions do not agree.
The community version works like this. Average the floats of your ten inputs, then map that average onto the outcome skin's own minimum and maximum float caps. A cs.money walkthrough uses a worked example: five P2000 Amber Fade at 0.13 plus five P250 Splash at 0.11 gives an average of 0.12, and mapping that onto an AWP Boom, whose float range is 0.06 to 0.28, lands at roughly 0.126.
A lower average input float pushes the result toward better wear. Because each possible outcome has its own float caps, the same set of inputs can land in Factory New for one outcome and Minimal Wear for another.
Practical rules
1. Check that every collection in your contract has at least one skin in the next tier. One bad input can invalidate the whole set.
2. Keep StatTrak and normal skins in separate contracts.
3. Decide what you are chasing before you buy inputs. Mixing collections spreads the odds, it does not improve them.
4. Do not trade away a skin that is the top tier of its collection. It cannot be used, and it is often the skin people assume is safe to dump.
FAQ
Does the price of my inputs matter?
No. The contract reads rarity and float.
Can I get a knife from ten Covert skins?
No. The knife and glove contract takes five Covert skins.
Are Souvenir skins usable?
No. Souvenir and star quality items are excluded, while StatTrak items are allowed as long as the whole contract is StatTrak.
Why does the contract refuse my Tec-9 Ossified?
It is the highest tier skin in the Aztec Collection, and top tier items cannot be used as inputs.
Is the float of my result random?
Liquipedia says yes. Community formulas and most calculators say the input floats decide it. Valve has not published a formula either way.
Sources
[1] Liquipedia: Trade Up Contract
[2] Counter-Strike Wiki: Trade Up Contract
[3] cs.money: Guide to CS2 Trade Up Contracts