CS2 Trade-ups Explained & How to Calculate Odds

Trade-ups in CS2 allow a player to get one skin from the next rarity level by offering ten skins of a lower rarity level. Although at first glance, the results available after a combination of collections can seem random, it is possible for you to determine the probability of getting each of the possible results once you know which collections have been chosen for inputs.

A CS2 trade-up calculator can change a complicated contract into a clear set of numbers. Enter a list of skins intended for use, then see the most likely outputs, each collection's contribution to the total probability, and the estimated float of the results. 

It is especially helpful for contracts with a mix of collections because the probability can become a complicated calculation the mind may not be able to handle. The calculator can also help you weigh the pros and cons of different setups by simulating different contracts.

In most cases, trade-ups are simple. You supply ten skins of the same rarity, and you get a skin of the rarity level immediately above them.

Let us have some examples:

Of course, inputs can come from diverse collections, and this allows for different probability settings. A careful selection of mixed collections can, on the one hand, increase the share of certain output categories. This is why professional traders, as a rule, do the whole trade-up planning in advance; they don't even buy anything to have a complete picture.

Each skin used adds to the weight of the collection it belongs to. If a contract is made up of ten skins, one skin makes up ten percent of the chance.

If you used seven skins from Collection A and three from Collection B, Collection A would get 70 percent, whereas Collection B would get 30 percent of the chance.

Then, divide the chance share of each collection by the number of outputs that are eligible for the next level rarity.

If collection A has two eligible outputs:

70% ÷ 2 = 35% per skin

If collection B has three:

30% ÷ 3 = 10% per skin

Finally, all result percentages should add up to, or close to, 100%; hence, the number of potential outputs is very important. For example, two possible outputs from a collection mean each gets a larger share of the chance than those from a collection with five outputs, provided the number of skins in the contract is the same for both collections.

A skin's probability decides which skin might come out, whereas float measures its condition.

Each input skin has two values: the float itself and the allowed float range. These values determine how far its float is within its range, and they are ultimately used to average and determine the result skin's float range, as we understand it today. 

A clean float might help a clean outcome, but one also has to consider that each skin's range can be different. For example, different outputs with similar visible float values may not be equally desirable, because their allowed float ranges affect the output differently depending on the desired skin condition (Factory New, Minimal Wear, or Field Tested).

A trade-up analysis of a contract should not only look into the probability of getting the most expensive skin. It is also a good idea to find out:

Moreover, you can figure out the expected value by multiplying the probability of each possible outcome by its value, then adding them up.

If you understand how collection structure, probability, float, and price interact in a trade-up, figuring out good or bad deals becomes much faster.

If the whole contract consists of items from the same collection that has, say, one unique skin at its lower level, then that skin is the only possible outcome.

The Tradeit website lets users view various CS2 skins and compare options before finalizing the contract.

No, it will not. What matters is the collections, the quantities of inputs per collection, and the number of eligible skins. Even if you place your selected skins in a different order, their overall effect on the chance of a certain outcome will still be the ​‍​‌‍​‍‌same.