CS2 Case Odds: Knife Chances, RTP and Expected Value
What are the odds of unboxing a knife in CS2? It depends on where you open the case. Official CS2 cases in the game use fixed odds set by Valve. Case sites set their own odds for every case, and list them on the case page. This guide covers both, and shows how to work out whether a case is worth its price.
Official CS2 case odds
Every official weapon case in CS2 uses the same odds by rarity. Valve published them in 2017, when China required loot box odds to be disclosed:
| Rarity | Chance |
|---|---|
| Mil-Spec (blue) | 79.92% |
| Restricted (purple) | 15.98% |
| Classified (pink) | 3.20% |
| Covert (red) | 0.64% |
| Rare Special Item (knife or gloves) | 0.26% |
A 0.26% chance means about 1 knife or pair of gloves in every 385 cases on average. That is an average, not a promise: you could unbox one in your first case or go a thousand without one. On top of the rarity, about 1 in 10 items comes out as StatTrak™, and the wear and pattern are random too, so the chance of one specific knife in a specific finish is far smaller.
Each official case also needs a key, which costs $2.49 in the US and a similar amount in other currencies. At 385 cases, that is close to $1,000 in keys alone for one knife on average, before the price of the cases themselves.
CS2 case site odds
Case sites do not use Valve's cases. They build their own, fill them with skins from the market, and set a drop chance for every item. That means:
- Odds differ for every case. Some cases give a 1% chance at a knife, others 0.01%. The case page should list every item with its chance before you open it.
- There are no keys. You pay the case price and nothing else.
- You can calculate the value. Because the site lists the prices and the odds, you can work out exactly what a case is worth on average.
How to calculate a case's expected value
The expected value (EV) is the average value of what comes out of a case. To work it out, multiply each item's price by its drop chance and add the results up.
Take a case that costs $5.00 with four items:
| Item | Price | Chance | Price × chance |
|---|---|---|---|
| Knife | $300.00 | 0.5% | $1.50 |
| Rifle skin | $20.00 | 5% | $1.00 |
| Pistol skin | $3.00 | 30% | $0.90 |
| Cheap skin | $0.50 | 64.5% | $0.32 |
| Expected value | $3.72 |
The case costs $5.00 but is worth $3.72 on average, so its return to player (RTP) is 3.72 ÷ 5.00 = 74%. Open it many times and you should expect to get back about 74 cents for every dollar.
Real case sites are usually far better than that example, often somewhere between 85% and 95% RTP, but it varies from case to case and site to site. Some sites publish the RTP of each case. Where they do not, the calculation above takes a couple of minutes.
What the odds do not tell you
- Variance. A case with a 90% RTP and a 0.1% chance at a $5,000 knife behaves very differently from a 90% case full of similar skins. The first loses most of the time and pays big rarely. The second pays back steadily.
- Whether the odds are real. Provably fair proves your roll was not changed after the fact. Where the fairness page shows the ticket ranges, compare them with the listed percentages. See Provably fair explained.
- Item prices. A site values items at its own prices. If you withdraw a skin and sell it, you may get more or less than the site said it was worth.
Using the odds to your advantage
- Compare the RTP of similar cases before you open any.
- Prefer cases with more mid-value items if you want steadier results.
- Use free cases and bonuses to open cases without risking your own money: see free CS2 cases without a deposit.
- In case battles, the case's EV still decides what the battle pays back on average.
No case, official or on a case site, is worth opening for profit in the long run. Treat what you spend as the price of the fun. Case opening is gambling and for adults only.
Looking for a site with fair cases and a good track record? Compare them in our rankings.