GUIDE INDEX

In case you prefer a video guide, here's a fantastic one by one of our partners, Tech-savvy Scientist.

Introduction

In this guide we'll fully cover how CS2 trade up contracts work. It's mainly created for beginners that want to know more about the world of trade ups. However, it's also suitable for advanced users that want to deeply understand the math behind trade ups.

This tutorial will help you learn the basic concepts, to understand how trade ups work, how to build profitable trade ups, how to manipulate the odds of the outcomes, how to find and buy cheap low float skins, a list of useful tools...

Basic concepts

• Contract: it is a functionality included in the game in which a player can combine 10 skins of the same category to obtain a higher category skin following probability algorithms. In other words, it is a way of "gambling" to turn low quality skins into better ones.
• Category or rarity: all skins in CS: GO are divided into several categories depending on their rarity. The rarer they are, the more exclusive they are and therefore more expensive. Among them we can find, from best to worst: Covert, Classified, Restricted, Mil-Spec, Industrial Grade, and Consumer Grade.
• Exterior: all CS: GO skins can appear, either by opening cases or by drops while playing, in 5 different conditions. Most skins have all 5 available, but there are others that may have 4, 3, 2, or even 1. In general, the newer the skin looks, the more value it will have on the market due to its demand. The 5 existing conditions, from highest to lowest quality, are: Factory New, Minimal Wear, Field-Tested, Well-Worn and Battle-Scarred.
• Floats: another factor that determines the exterior and how the skin looks is the float value. All skins have a minimum value and a maximum value, which are between 0 and 1. This float value is very important and plays an essential role in the world of contracts. Furthermore, it corresponds to one of the aforementioned types of exterior, specifically:
  • Factory New: between 0 and 0.07
  • Minimal Wear: between 0.07 and 0.15
  • Field-Tested: between 0.15 and 0.38
  • Well-Worn: between 0.38 and 0.45
  • Battle-Scarred: between 0.45 and 1
• StatTrak™: some skins opened in cases or obtained by drops can appear as StatTrak™ and will have a kill counter. Both StatTrak™ and normal skins can be used in trade up contracts, but cannot be mixed.
• Souvenir: other skins can be part of some exclusive collections called souvenirs. These cannot be used in trade up contracts.

Trade up functionality

It is a fairly straightforward concept. In CS: GO, you select 10 skins from the same rarity and, following algorithms with random probabilities, you will get a skin of higher grade.

In general, this system is designed so that the player loses. However, due to the volatility of CS: GO skins and the math behind trade up contracts, it is possible to make a profit in the long run through this mechanism.

To do this, we will have to take into account several fundamental factors such as the float average, the number of outcomes, the min. and max. float values of the outcome skins... We will cover all of this in the next section.

Trade up maths

Remember that you can use our Calculator during this tutorial to calculate all this data automatically and 100% safely.

How are the probabilities calculated?

Officially, there is no way to know which algorithm CS: GO follows to determine the odds of getting one skin or another. At TradeUpSpy, to calculate the probabilities of outcomes, we use the new theory based on the pool of outcomes. This algorithm has been tested by many users and focuses on the number of outcomes that a collection has in a given rarity to establish the probabilities.

For each skin that you add to a trade up, you have to see how many outcomes it has. The more it has, the more likely you are to get an outcome skin from the collection it belongs to. We are going to use the simile of ballots to better understand the process. For example, if I add 10 times a skin that has 3 outcomes, each individual outcome would have a weight of 10 ballots.

To better understand how it works, we are going to study a couple of examples. You can click on them to visually observe the examples presented in our calculator:

• Single collection trade up using Industrials from Dust 2:
  • It has 3 outcomes (SG 553, M4A1-S and Bizon).
  • By putting 10 inputs, we would have:
    • 10 SG 553 ballots.
    • 10 M4A1-S ballots.
    • 10 Bizon ballots.
    • A total of 30 ballots.
  • When calculating the probability of each skin, we would have:
    • 10/30 odds of getting SG 553 (33.33%).
    • 10/30 odds of getting M4A1-S (33.33%).
    • 10/30 odds of getting Bizon (33.33%).

• Double collection trade up using Mil-Specs from Dust 2 and Control:
  • Dust 2 has 1 outcome (P2000).
  • Control has 3 outcomes (Five-SeveN, UMP-45 and FAMAS).
  • By putting 9 Dust 2 inputs and 1 Control input, we would have:
    • 9 P2000 ballots (Dust 2).
    • 1 Five-SeveN ballot (Control).
    • 1 UMP-45 ballot (Control).
    • 1 FAMAS ballot (Control).
    • A total of 12 ballots.
  • When calculating the probability of each skin, we would have:
    • 9/12 chances of getting P2000 (75%).
    • 1/12 chance of getting Five-SeveN (8.33%).
    • 1/12 chance of getting UMP-45 (8.33%).
    • 1/12 chance of getting FAMAS (8.33%).
  • Initially, one might think that by putting 9 skins from Dust 2, there is a 90% chance of getting a superior skin from the same collection. However, as we have seen in this example, this is not the case.

How are the exteriors of the outcomes calculated?

Another important aspect of trade ups is the average float used. It is not the same to use 10 skins in Factory New than 10 in Field-Tested condition. Depending on the starting weapons, we may get one exterior or another. Once the importance of floats in contracts is understood, it is essential to ALWAYS check that the exterior of the outcome skins are as desired. A tiny 0.01 error on a float could result in an output skin in Minimal Wear (or even worse) instead of Factory New.

When you add skins to a trade up, their float value is added until you have 10. Once the 10 input skins have been added, the average float of the contract will be calculated. This is done by taking the value of the sum and dividing it by 10. An example:

• We add to a trade up 3 Factory New skins with a float value of 0.02
• We subsequently add 7 Minimal Wear skins with a float value of 0.11
• The average float will be the sum of these floats divided by 10: (0.02 + 0.02 + 0.02 + 0.11 + 0.11 + 0.11 + 0.11 + 0.11 + 0.11 + 0.11) / 10 = 0.083

This average is one of the necessary values to know which exterior the output skins will have.

Another important value is related to the float limits of a skin. As we have commented previously, all skins have a minimum and a maximum float, which will be between 0 and 1. This will allow a skin to be, for example, Factory New or not. You can check the minimum and maximum floats of all CS: GO skins in our database.

After seeing the previous concepts, the formula that must be applied to each outcome to know its exterior is:

outcome skin float = ((max.float-min.float) × avg.float) + min.float

Let's use the previous trade up as an example:

• 9 skins from the Dust 2 collection with float 0.035
• 1 skin from the Control collection with float 0.035
• We get an avg. 0.035 float
• To obtain the float / exterior of each outcome, we calculate:
  • P200 | Amber Fade:
    • min. float: 0
    • max. float: 0.40
    • final float: ((0.4-0) × 0.035) + 0 = 0.014
  • UMP-45 | Crime scene
    • min. float: 0
    • max. float: 0.75
    • final float: ((0.75-0) × 0.035) + 0 = 0.02625
  • Same process for the other skins.

As you can see, checking the avg. float and the min / max of each skin is very important to avoid obtaining erroneous results.

From here, how do I build profitable contracts?

Take a look at one of the following sections by the name “How to find profitable trade ups”.

Manipulating odds & filler skins

Now that we have learned how trade up contracts work internally, it is very important to know how we can manipulate outcomes to get the skins we want.

Since the outputs of the trade ups are based on the number of outcomes that the entry skins have (simile of the ballots), we can use this to our advantage.

If we look again at the Dust 2 and Control trade up, even though we have introduced 9 Dust 2 skins, we have a 25% chance of getting one of the Control skins. This is because Dust 2 only has one outcome, if we used another collection with more outcomes, this percentage would drop.

Skins that have few outcomes, like those in Dust 2 Mil-Spec, are known as filler skins. As their name suggests, they are used to fill a trade up without raising the price too much and without altering the chances of obtaining the desired skin too much. These skins, due to their particularity, are very demanding and can be difficult to obtain.

Visit our filler skins page to find an up-to-date list of all skins used for this purpose.

Cheapest ways to get input skins and low floats

There are several methods you can use to find cheap input skins with low floats. Among them, we can highlight:

• Steam Marketplace refresh: update the Steam Marketplace every so often to quickly purchase any skin that appears with a low float. Although it is quite effective, especially with popular weapons, it requires a lot of patience and dedication.
• Steam Marketplace buy orders: put cheap buy orders for large quantities of a skin. The good thing about this method is that you will find very low floats from players who do not know this world and just want to get some money. The downside is that skins with high floats that are not worth you will have to exchange or sell them again, losing some money due to Steam fees.
• External marketplaces: there are many external markets that are dedicated to buying and selling skins for real money that tend to have low floats. Some of them are:
  • SkinSnipe (price comparison tool)
  • CSMoney
  • Skinport
  • SkinBaron

You have a complete list of external markets with their details in this link.

In case you are wondering how you can see float values quickly from the Steam market itself without having to enter the game, there is a very popular browser extension called CSGOFloat Market Checker that performs this function.

How to find profitable trade ups

There are plenty ways to find profitable trade ups:

• Our weekly trade ups: every week we show a new trade up to our community on the “hot trade ups” page. These contracts are verified to ensure their profitability.
• Learning the best combinations and splits: we have a page called “trending data” that collects popular combinations that users are using. In addition, you can check which floats they use for their trade ups and other information of interest.
• Joining our Discord: our community posts new trade ups constantly. Furthermore, we discuss about CS2 economy and other stuff of interest.
• Checking our partners: you can find a list of our affiliates at the bottom of the trade ups page. Our collaborators upload new quality trade ups videos constantly.

Useful tools

Finally, here’s a summary of the most useful tools that you can use to improve your trade up game:

• Hot trade ups: weekly profitable trade ups.
• Calculator: our trade up contract simulator.
• Price check: useful tool to find cheap skins for sale on third party marketplaces.
• Skins: full CS2 skin database with skin and collection details (prices, min and max float…)
• Trending data: great to find popular trade up combinations and splits.
• Filler skins: fillers breakdown by rarity.
• SkinSnipe: skin price comparison.