Opening CS2 cases: keys, drop odds and rarity

How does opening a case work?

A case holds a set of skins, ordered by rarity. To open it you need a key. After opening you receive a random skin from the contents — which one exactly is decided by the drop chance of each rarity. The rarer the tier, the lower the probability. The contents and odds are known in advance and publicly for each case.

Case and key

You get a case as a free random drop after playing, but to open it you need a key. Without a key the case just sits in your inventory. The key is therefore the stake of opening — which is why it pays to know the odds first.

Drop odds by rarity

The probability distribution is fixed for classic cases. Roughly, it looks like this:

Rarity	Colour	Approximate chance
Mil-Spec	blau	~79,92 %
Restricted	lila	~15,98 %
Classified	pink	~3,2 %
Covert	rot	~0,64 %
Messer / Handschuhe	gold	~0,26 %

StatTrak™ and rare variants

Any skin that drops can also appear in the StatTrak™variant, which counts your kills with that item. The chance of StatTrak is lower than the normal variant, and for knives and gloves (Gold) the drop is the rarest of all. These are exactly the items that carry the value of a case.

Cases, upgrade or trade-up?

Opening cases is a pure random drop from fixed contents. The Upgrade lets you pick the target and see the chance in advance, the Trade-Up combines ten skins into a higher one.

• Cases: a random skin from the contents, chance by rarity.
• Upgrade: you choose the target, chance before you start.
• Trade-Up: 10 skins → one a tier higher, via float and collection.

Float and value of the skin that drops

With cases too, the Float (condition) sets the price. Two identical skins can differ sharply in value depending on wear.

Kategorie	Float-Bereich	Value
Factory New	0.00 – 0.07	highest
Minimal Wear	0.07 – 0.15	hoch
Field-Tested	0.15 – 0.38	mittel
Well-Worn / Battle-Scarred	0.38 – 1.00	niedriger

More on float in the Guide, and on selling and value in the Skins.

How to approach opening

Treat opening as entertainment with a fixed probability, not an investment. The rarest items sit at hundredths of a percent — realistically it is more likely to be a blue or purple skin. Set yourself a limit for the number of cases and stick to it.

Responsible play

Opening cases involves an element of chance and is strictly for people aged 18 and over. Set yourself limits, only stake what you are willing to lose. Help: BeGambleAware.org.

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Weiterlesen: CS2 trade-up calculator · Guide: float and provably fair · The value of CS2 skins

How to budget for opening cases

Because every case has a fixed, publicly known set of drop odds, the sensible way to play is to decide in advance how many cases you will open and treat that as the whole budget. The rarest items — knives, gloves and red Covert skins — sit at hundredths of a percent, so realistically most opens return a blue or purple skin worth less than the key. Knowing that before you start is what separates entertainment from chasing a loss. If a specific skin is the goal, compare the cost of opening toward it with simply buying it: the purchase is almost always cheaper and certain.

Cases, the upgrader or trade-up — which costs less?

All three routes can hand you a better skin, but they differ in control and in how the house edge is applied. Opening a case is a pure random draw from fixed contents; the upgrader lets you pick the target and see the chance first; a trade-up combines ten skins of one rarity into a single higher one. None of them beats buying a specific skin outright on value — each carries an edge — so pick the one whose mechanic you enjoy, not the one you think is a shortcut to profit.