Question 1

How are the odds of a specific skin calculated?

Accepted Answer

A collection’s chance equals the share of its items in the contract, and inside that collection the result is drawn uniformly from every skin of the next rarity. Seven inputs from a collection with four outcomes give each of them 7/10 ÷ 4 = 17.5%, while three inputs from a collection with five outcomes give 3/10 ÷ 5 = 6%.

Question 2

How is the output wear determined?

Accepted Answer

Each input’s float is normalized inside its own range: (float − min) ÷ (max − min). The average of those ten numbers is projected into the range of the skin you get: output float = min + average × (max − min). That is why the same set of inputs can land in different wears with very different prices.

Question 3

Why a range instead of a single profit number?

Accepted Answer

Markets publish prices per wear bucket, not per float, so ten “Field-Tested” purchases can land anywhere inside that bucket. Usually the entire profit of a trade-up is one expensive outcome that stays in its good wear on a lucky float and drops into the next one on an unlucky one. The lower figure is the worst float inside the wear, the upper one the best, and the middle figure assumes you buy ten random listings without checking floats.

Question 4

Can a contract give a knife or gloves?

Accepted Answer

Yes: since October 2025 five Covert items from one collection are exchanged for a knife or gloves from that collection. Five StatTrak™ Covert items give a StatTrak™ knife — StatTrak™ gloves do not exist. This is the only five-item contract; every other transition takes exactly ten inputs.

Question 5

Does a contract accept Souvenir items?

Accepted Answer

Yes, since May 2026 Souvenir items go into a contract alongside normal ones: every Souvenir attribute — stickers and tournament marks — is removed and the result is a normal item of the next rarity. Souvenirs cannot go into a StatTrak™ contract. We pick the Souvenir version of an input when it is cheaper than the normal one and has enough listings.

Question 6

How is this different from a normal trade-up calculator?

Accepted Answer

A calculator shows what a contract would cost at the average wear price. We show a basket you can buy: ten specific lots with floats, prices and links, plus the exact result float for that set.

Question 7

Is there a free alternative to TradeUpSpy?

Accepted Answer

Yes, this page. Basket building, EV, ROI, outcome odds and lot links are free and need no account, and the lots are pulled from several markets at once instead of a single one.

Question 8

How often is the data updated?

Accepted Answer

The top list is recomputed in the background every thirty minutes, and listings for a given skin are cached for ten minutes. Each basket page has a "Refresh listings" button that queries the markets again.

Question 9

Why does a basket sometimes fail to assemble?

Accepted Answer

If the markets do not have ten listings with the required float and price, the basket remains incomplete and shows the number found. Lower-tier transitions fill more often than knife contracts.

CS2 Trade-Up Contracts