How are CS2 trade-up odds calculated?

Since the October 23, 2025 update the game picks one of your inputs at random (each input carries 10% in a standard contract, 20% in a 5-item Covert contract), then picks one of the higher-rarity skins of that input's collection uniformly. The probability of a specific outcome is (inputs from its collection ÷ total inputs) × (1 ÷ number of possible outcomes in that collection).

How is the output float calculated?

Each input float is first normalized to that skin's own wear range: (float − min) ÷ (max − min). The average of those normalized values is then mapped onto the outcome skin's range: output = outMin + average × (outMax − outMin). Before October 2025 the plain, un-normalized average was used.

What changed in the October 2025 trade-up update?

Three things: odds reverted to per-input weighting (collections with a single outcome got much stronger), the output float switched to the normalized average, and 5 Covert items from weapon cases can now be traded up into a knife (or gloves; StatTrak Coverts yield StatTrak knives).

Can I use Souvenir skins in trade-up contracts?

Yes — since May 22, 2026 Souvenir items can be mixed with normal items of the same rarity. Souvenir attributes are stripped and the result is always a normal-quality item.

Can I trade up to a knife in CS2?

Yes. 5 Covert skins from weapon-case collections trade up into that case's knife or glove pool. Map-collection Coverts (e.g. Dragon Lore) still cannot be traded up. Valve does not publish the sub-odds inside the gold pool, so knife EVs are estimates assuming a uniform roll.

CS2 Trade-Up Calculator

Exact odds & output floats with the current post-2025 formula — live prices from the marketplace of your choice.

Rarity

Prices

Inputs

Restricted

0 / 10

Your Steam inventory

Result

Classified

Add 10 skins to see odds, floats and expected value.

Cost —

Expected value —

ROI —

Profit chance —

	Outcome	Odds	Float	Price	Net

How trade-up contracts work

The rules (2026)

10 skins of one rarity become a single skin of the next rarity, drawn from the collection of one of your inputs. Since October 23, 2025, 5 Covert skins from weapon-case collections trade up into that case's knife or glove pool. StatTrak™ is all-or-nothing, and since May 22, 2026 Souvenir items may be mixed in — attributes are stripped, the output is always normal quality. Collections without a higher rarity (and Contraband) are ineligible; the crafted item carries a 7-day trade hold.

The odds formula (current, since October 2025)

The game picks one of your N inputs at random — each input carries 1/N — then rolls one of that input's collection outcomes uniformly:

P(outcome) = (inputs from its collection ÷ N) × (1 ÷ outcomes in that collection)

One input from a single-outcome collection plus 9 fillers gives a flat 10% — under the 2019–2025 outcome-weighted formula it was ≈5.3%. Many calculators still ship the old formula; this one implements the current per-input rules.

The output float formula (normalized since October 2025)

Every input float is normalized to its own skin's wear range, averaged, and mapped onto the outcome's range:

norm = (float − min) ÷ (max − min) → output = outMin + avg(norm) × (outMax − outMin)

Ten inputs capped 0.10–0.70 at float 0.15 average 0.083, not 0.15 — on an outcome capped 0.00–0.50 that's a 0.042 Factory New. Before October 2025 the plain average was used.

Knife contracts & limitations

Only Coverts from weapon/glove cases reach a gold pool; map-collection Coverts (Dragon Lore, Medusa …) remain final.
Gold-pool sub-odds (knife, finish, phase) are unpublished — a uniform roll is assumed and marked as an estimate.
StatTrak Covert contracts yield StatTrak knives; glove-case StatTrak Coverts are unusable (no StatTrak gloves exist).
Doppler-phase outcomes roll their phase separately; prices use the base entry or the cheapest phase.

FAQ

Why do my odds differ from other calculators?
Several tools still implement the 2019–2025 outcome-weighted formula. Valve quietly reverted to per-input odds in the October 2025 update.

Where do the prices come from?
From the marketplace you pick in the Prices selector, refreshed every 15 minutes. Items that marketplace doesn't list fall back to the cheapest live sell price across 13 markets (bid feeds ignored).

Does the calculator execute trade-ups?
No — it models odds, floats and expected value; the contract happens in-game. Recently traded items may be blocked by the 7-day trade protection.