TF2 Trade-Up Odds Explained: Single and Mixed Collections

Ten items from one collection

For a normal item-grade trade-up, ten eligible inputs of the same grade produce one output from the next grade. With all ten inputs from one collection, that collection receives the entire output probability. Within that eligible next-grade pool, outputs are equally likely.

For example, if the next grade has four eligible items, each has a 1 ÷ 4 = 25% chance. If there is only one eligible next-grade item, its item-type probability is 100%; that still does not guarantee its market value or a profit.

Mixing collections: split the collection share first

First divide the input count from each collection by ten. Then divide that collection’s probability by its number of eligible next-grade outputs. Item probability = (inputs from its collection ÷ 10) ÷ eligible outputs in that collection.

Illustrative example: five inputs from collection A and five from collection B give each collection a 50% share. If A has five next-grade outputs, each A output has 10% probability. If B has eight, each B output has 6.25%. The thirteen items are not all equally likely.

Changing the mix to six A inputs and four B inputs changes those per-item odds to 12% for each A output and 5% for each B output. The total still adds to 100%.

Grade, Strange quality and wear still matter

The calculator locks compatible input grades once you add your first item, and it keeps Strange and Non-Strange contracts separate. A highest-grade item cannot be upgraded into a nonexistent next tier.

For War Paints and decorated weapons, select the exact wear and quality before comparing quotes. The outcome pool and the price lookup are different questions: getting an item’s name right does not make a quote for another wear valid. Use the calculator’s actual output table instead of assuming that every variant shares one price.

Chance of profit is not ROI

Chance of profit is the sum of the probabilities of outputs worth more than your total input cost, using net output values. Break-even outcomes are not profitable outcomes. If an output is unquoted, do not assume that the displayed share of quoted winning outcomes describes the entire contract.

Expected ROI averages the value of every quoted outcome. A rare expensive item can raise expected ROI while most outcomes still lose. Review both numbers before comparing recipes.

Trade-up odds are not case-opening odds

Opening a case and trading up items are different processes. Do not apply case-opening grade percentages to a ten-item contract. Use a collection guide to inspect its next-grade items, then load the intended grade and quality into the calculator.

An opening calculation also needs the case and opening-key cost. A normal item-grade trade-up instead consumes its input items. This distinction matters when comparing costs and potential returns.