CS2 Case Odds Calculator
Enter how many cases you plan to open and what the key and case cost — the calculator shows the odds for every rarity and the real price of a knife.
How we calculate
In 2017 Valve had to publish case odds for the Chinese release of the game, and the table has not changed since: a blue item drops in 79.92% of openings, purple in 15.98%, pink in 3.2%, red in 0.64%, and a knife or gloves in just 0.26%. On top of that, one item in ten is StatTrak.
Every opening is independent: past bad luck does not raise your next chance. So the chance of at least one knife from N cases is 1 − 0.9974 to the power of N. On average a knife drops once per 385 cases, but a solid 90% chance takes 885 openings, and 99% takes 1,769.
The price of one opening is the key plus the case. A key costs $2.49 in the in-game store; cases are bought on the market and their price depends on the collection. The calculator does not value the skins you get, because market prices change daily.
Sources
checked 30 September 2026
Questions and answers
Are the odds the same in every case?
Yes. The odds table is shared by all regular weapon cases: only the skins inside differ, not the probability of each rarity.
Do my odds go up after a long dry streak?
No. Every opening is independent and the game does not push you toward a knife. After 300 empty cases, the next one is still 0.26%.
Is opening cases worth it?
The calculator does not value skins, because market prices keep moving. But almost four out of five openings give a blue item — the lowest rarity in the case — so it pays to decide in advance how much you are willing to spend.
How much does a key cost?
$2.49 in the in-game store, and that price has not changed for years. Keys you buy cannot be sold or traded; they only open a case from their own collection.
Unofficial tool. Not affiliated with Valve.