Every trade-up contract is a bet. You know the possible outcomes, you know the probabilities, and you can calculate the expected value before you commit. But most traders fixate on EV and ignore the metric that actually determines whether they make money: chance-to-profit.
How Trade-Up Probabilities Work
When you submit 10 inputs spanning multiple collections, the game picks one output skin from the next rarity tier. The probability of each outcome is proportional to how many inputs came from that skin's collection.
Say you use 7 inputs from Collection A (which has 2 skins at the next rarity: Skin X and Skin Y) and 3 inputs from Collection B (which has 1 skin at the next rarity: Skin Z). The weights are:
- Collection A total probability: 7/10 = 70%
- Collection B total probability: 3/10 = 30%
Within Collection A, each next-rarity skin gets an equal share: Skin X = 35%, Skin Y = 35%. Collection B has only one option: Skin Z = 30%.
This weighting is deterministic. There's no hidden RNG on top of it — the game generates a random number, maps it to these weights, and you get that outcome. Over enough trade-ups, your results will converge on these exact probabilities.
Expected Value: The Formula
Expected value is the probability-weighted average of all outcomes minus your input cost. The formula:
EV = sum(probability_i * output_value_i) - total_input_cost
Using our example above, suppose Skin X is worth $120, Skin Y is worth $40, Skin Z is worth $200, and your total input cost is $80:
EV = (0.35 * $120) + (0.35 * $40) + (0.30 * $200) - $80
EV = $42 + $14 + $60 - $80 = $36
Positive EV. On average, this trade-up returns $36 profit per attempt. Run it 100 times and you'd expect roughly $3,600 in total profit. That's the theory.
Why EV Alone Is Misleading
That $36 EV number hides important information. Look at the individual outcomes:
- Skin X ($120): 35% chance, profit = $40
- Skin Y ($40): 35% chance, profit = -$40 (loss)
- Skin Z ($200): 30% chance, profit = $120
Chance to profit: 65% (Skin X + Skin Z). Chance to lose: 35% (Skin Y). The expected value is positive, but you lose money more than one-third of the time. If you run this trade-up once and hit Skin Y, you're down $40. The $36 EV is real, but it only materializes over many repetitions.
Now consider a different trade-up: 100% chance of one output worth $84, input cost $80. EV = $4. Boring. But you literally cannot lose. Every single execution makes $4. For someone doing one trade-up, the $4 guaranteed profit beats the $36 EV gamble that has a 35% chance of losing $40.
Chance-to-Profit: The Practical Metric
Chance-to-profit measures the probability that the trade-up produces an output worth more than your total input cost. It doesn't care how much you profit or lose — just whether the result is green or red.
A trade-up with 90% chance to profit is one where 9 out of 10 outcomes are worth more than your inputs. You might profit $5 on the good outcomes and lose $30 on the bad one, with EV of +$1.50. The EV is tiny, but you almost always come out ahead.
A trade-up with 20% chance to profit but high EV is the opposite: most attempts lose money, but the rare win is big enough to pull the average positive. This is a lottery ticket with favorable odds. Mathematically sound, emotionally brutal.
Neither metric alone tells the full story. You need both.
Risk Profiles: Lottery vs Grinder
The Lottery profile: low chance-to-profit (15-35%), high EV. These trade-ups have one or two expensive outcomes and several cheap ones. You lose most of the time, but the wins are large. A knife trade-up where 4 out of 5 possible outputs are worth less than your inputs, but the 5th is a $3,000 Karambit Fade, fits this profile. EV might be +$80, but you're losing money 80% of the time.
This works if you have the bankroll to absorb repeated losses and the volume to let expected value converge. Ten attempts at $200 each ($2,000 total outlay) with 20% chance to profit and +$80 EV should net ~$800 profit over those 10 attempts — but you might need to survive 6-7 losses in a row before hitting a winner. Can your bankroll handle that?
The Grinder profile: high chance-to-profit (75-100%), modest EV. These trade-ups have most or all outcomes above breakeven. Individual profits are small — $3 to $15 typically — but losses are rare. A Classified-to-Covert trade-up where 8 of 10 outcomes are profitable and the other 2 lose only a few dollars fits here.
This works for smaller bankrolls and traders who want predictable income. Ten Grinder trade-ups at $50 each ($500 outlay) with 85% chance to profit and +$5 EV should net ~$50 with very low variance. You won't get rich quickly, but you won't go broke either.
When Negative EV Trade-Ups Make Sense
This sounds contradictory, but negative EV trade-ups can be rational under specific conditions.
Suppose a trade-up has -$5 EV but 60% chance to profit, with the following outcome distribution: 60% chance of +$15 profit, 40% chance of -$35 loss. Expected value is (0.6 * $15) + (0.4 * -$35) = $9 - $14 = -$5. The math says don't do it.
But what if the 40% loss outcome produces a skin you actually want to keep and use? Or what if the $15 profit outcome produces a skin with high trade velocity that you can flip immediately, while the loss outcome is a skin that will eventually recover in value? Context matters beyond raw EV.
TradeUpBot flags trade-ups with negative EV but above 25% chance to profit, specifically because some of them have profiles worth considering. A trade-up with -$3 EV but 70% chance to profit and a worst-case loss of only $8 is a mild gamble with mostly good outcomes. The expected value is slightly negative, but the actual experience of running it is usually positive.
The opposite is also true: positive EV doesn't automatically make a trade-up worth doing. A +$50 EV trade-up with 5% chance to profit and $500 input cost means you lose money 95% of the time and need to do it 20+ times for the EV to converge. Unless you have $10,000+ allocated to this single trade-up type, the variance will eat you alive.
Putting It Together
The best trade-ups score well on both metrics: positive EV and high chance-to-profit. These are rare, which is why discovery engines exist — manually finding trade-ups where most outcomes are profitable AND the expected value is meaningfully positive requires evaluating thousands of listing combinations.
When you have to choose between the two metrics, let your bankroll decide. Large bankroll with high volume? Optimize for EV. You'll weather the variance. Small bankroll, doing a few trade-ups per week? Optimize for chance-to-profit. Consistency beats expected value when you can't afford a losing streak.
TradeUpBot lets you sort by either metric. Sort by profit (EV) to find the highest-upside plays. Sort by chance to find the most consistent ones. Expand any trade-up to see the full outcome distribution — every possible output, its probability, and whether it's above or below breakeven. That distribution is the trade-up. Everything else is just a summary of it.