CS2 Trade Up Probability Guide

Understanding trade up probability is the foundation of profitable trade ups. This guide explains exactly how the CS2 trade up system determines which outcome you receive, how to calculate probabilities, and how to manipulate them in your favor.

The Collection Weighting System

Trade up probability is entirely determined by the collections your input skins belong to. Each of the 10 input skins contributes exactly 10% weight to its collection. If 8 skins come from Collection A and 2 from Collection B, Collection A receives 80% of the total probability and Collection B receives 20%.

Within each collection, the probability is distributed equally among all available outcomes at the target rarity tier. If Collection A has 3 possible outcomes at the next tier, each outcome gets 80% / 3 = 26.67% probability. If Collection B has 1 outcome, that single outcome gets the full 20%.

Probability Examples

Consider a Mil-Spec to Restricted trade up with 10 inputs:

Scenario	Collection A	Collection B	Probability Split
10/0 split	10 inputs (100%)	0 inputs	All outcomes from A only
7/3 split	7 inputs (70%)	3 inputs (30%)	70% to A outcomes, 30% to B
5/5 split	5 inputs (50%)	5 inputs (50%)	Equal 50/50 split
9/1 split	9 inputs (90%)	1 input (10%)	90% to A, 10% to B

Maximizing Your Desired Outcome

To maximize the probability of a specific outcome, you want to put as many inputs as possible from that outcome's collection while minimizing the total number of outcomes from that collection. The ideal scenario is a collection with only 1 skin at the target tier — then every input from that collection goes entirely toward that one outcome.

Conversely, if your desired outcome is in a collection with 4 possible results at the target tier, even using all 10 inputs from that collection only gives you a 25% chance of hitting the specific skin you want. In this case, it may be worth looking for the same skin in a different collection with fewer outcomes.

The Guaranteed Outcome Strategy

Some collections have only 1 skin at certain rarity tiers. If you use 10 inputs from such a collection, you are guaranteed to receive that specific skin. This strategy eliminates probability risk entirely and turns the trade up into a pure cost-vs-value calculation. The only question becomes whether the output value exceeds your total input cost.

Multi-Collection Strategy

Advanced traders sometimes split inputs across collections deliberately. For example, you might put 9 inputs from Collection A (targeting a high-value outcome) and 1 from Collection B (which happens to have cheaper inputs at the same rarity). This gives you a 90% chance of a Collection A outcome while reducing total input cost. The 10% risk of a Collection B outcome is acceptable if the cost savings are significant enough.

Common Probability Mistakes

The most common mistake is assuming that trade up probability works like case odds — it does not. Unlike cases, where you have no control over outcomes, trade ups let you directly influence probability through collection selection. Another mistake is ignoring how many outcomes exist at the target tier. A collection might seem attractive, but if it has 5 outcomes at the next tier, your probability is spread thin across all five.

Players also often forget that each individual trade up is independent. Previous results do not affect future outcomes. Getting an undesirable result multiple times in a row does not increase your chances of a good result next time.

Calculate Your Probabilities

Use our trade up calculator to see exact probabilities for any combination of inputs. Enter your 10 skins and the calculator will show every possible outcome with its precise probability.

Frequently Asked Questions