CS2 Trade-Up Guide

CS2 Trade-Up Expected Value (EV), Profit Chance, and ROI Explained

What does expected value mean for a CS2 trade-up?

Expected value is the long-run average value of the contract's output if the same prices and probabilities could be repeated many times. It is not a prediction that your next output will be worth the EV amount.

Gross EV = Σ (probability × market price)
Net EV = Σ (probability × realistic proceeds after selling costs)
Expected profit = net EV − input cost
Expected ROI = expected profit / input cost

Use net EV to make decisions. Gross EV can make a contract look profitable even when marketplace fees and the bid/ask spread turn it negative.

How do you calculate EV with a worked example?

Suppose a $15 contract has four outcomes. The values below are already reduced to realistic net proceeds:

Net EV is $15.30. Expected profit is $0.30 and expected ROI is 2%. But only the $20 and $45 outcomes beat the $15 cost, so the probability of profit is 30%. This positive-EV contract still has a 70% chance of losing money on one attempt.

What is the difference between ROI and profit chance?

ROI measures the probability-weighted size of gains and losses. Profit chance counts how often an outcome finishes above break-even. A rare, very valuable result can make EV positive while most outcomes lose. Conversely, a contract can win often but have one severe downside result that makes EV negative.

Look at both metrics, plus the worst-case loss. There is no single percentage that captures every useful feature of the distribution.

Which price should you use for each output?

Use the amount you can plausibly receive, not an optimistic listing:

• Match the predicted output wear and, when the market pays for it, the float band.
• Prefer executable bids or recent liquid sales over one unusually high ask.
• Subtract the actual marketplace seller fee.
• Include withdrawal or currency-conversion cost when you need cash proceeds.
• Discount illiquid items that may require a price cut to sell.

See Steam versus third-party marketplace fees for why the same output can support different EV figures on different venues.

How do collection odds affect EV?

Every output needs its own probability. For mixed collections, first assign each collection its share based on input count, then split that share among eligible outputs. Our probability guide provides the complete formula and a 7/3 example.

A common spreadsheet error is to average all visible output prices equally. That works only when every individual outcome truly has equal probability.

What is a break-even input price?

If net EV is $18, then $18 is the theoretical total break-even cost. In practice you need room for price movement, execution errors, and resale friction. For 10 interchangeable inputs, a first-pass average cap is:

Break-even cost per input = net EV / 10

Inputs are rarely interchangeable once float is considered. Allocate more of the budget to scarce low-float pieces only when they keep valuable outputs above a wear boundary.

How quickly can positive EV disappear?

Immediately. Input sellers adjust asks, buyers remove bids, and output prices move. The contract is a snapshot, not a permanent recipe. Reprice after assembling the basket and before submitting. If the current net EV no longer clears your required margin, walking away is cheaper than forcing the original plan.

How should you compare two positive-EV contracts?

• Expected ROI after all costs.
• Probability of profit and probability of a large loss.
• Worst-case proceeds.
• Output liquidity and expected time to sell.
• Difficulty of sourcing the required input floats.

A slightly lower ROI can be the more executable opportunity when its inputs are available and its outputs sell reliably. Mathematical EV is only useful if the assumed trades can actually occur.

Frequently Asked Questions