CS2 Trade-Up Contracts: The Math Behind Profitable Trade-Ups

The Trade-Up Contract: CS2's Most Profitable Gamble

The Basic Rules (No Exceptions)

• You submit exactly 10 skins of the same rarity tier (Consumer Grade, Industrial Grade, Mil-Spec, Restricted, Classified, or Covert).
• You receive exactly 1 skin from the next rarity tier up.
• The output skin is pulled from the collections that your input skins belong to.
• The output float is calculated from the average float of your 10 inputs, with minimum and maximum float caps applied per collection.

The Float Formula: Where Most People Get It Wrong

How Output Probability Works

• 7 AUG | Syd Mead (Industrial Grade, The AUG Collection)
• 3 P250 | Metallic (Industrial Grade, The P250 Collection)

• The AUG Collection's Mil-Spec tier (7/10 chance)
• The P250 Collection's Mil-Spec tier (3/10 chance)

• Probability of getting [Skin A] from Collection X = (Number of inputs from Collection X / 10) × (1 / Number of skins in Collection X's next tier)

Expected Value Calculation: The Money Math

• P250 | Visions - ~$2
• SSG 08 | Death Strike - ~$3
• MAG-7 | Copper Coated - ~$2
• UMP-45 | Scaffold - ~$2
• Galil AR | Signal - ~$2

• M4A1-S | Printstream - ~$80 (FN)
• USP-S | Monster Mashup - ~$5 (FN)
• MAC-10 | Whitefish - ~$3 (FN)

Float Distribution: The Hidden Variable

• If the collection has a FN cap of 0.07, you're guaranteed FN
• If the collection has a FN cap of 0.00 (like some knives), you'll get MW minimum

Profitable Trade-Up Patterns (Verified)

• 10 FN inputs averaging 0.03 float → output knife has 0.26 float (clamped)
• 10 BS inputs averaging 0.75 float → output knife has 0.75 float

The 10/10 Rule: Why Collection Mixing Matters

• M4A1-S | Flashback - $1
• SSG 08 | Fever Dream - $1
• P250 | Red Rock - $1

The Float Cap Exploit

Risk Management: The Real Talk

1. Float ignorance - Most players don't understand float averaging
2. Liquidity constraints - Some inputs are hard to buy in bulk
3. Risk aversion - People hate losing money on a single roll
4. Time premium - Profitable trade-ups require patience to source inputs

Tools of the Trade

• CS2Float for checking exact float values of inputs
• Skinport's trade-up calculator (not perfect, but decent for quick checks)
• My own spreadsheet that accounts for float distribution within each collection

EV = Σ (P_i × Price_i × Float_Probability_i) - Cost_Inputs

Final Word: The House Always Wins, But...