CS2 Case Odds & Expected Value (EV) Explained
What does a case opening actually return, bro? Here are the odds Valve officially published, and a calculator that turns them into expected value using today's prices.
Valve's published rarity odds
| Rarity | Odds per opening | Roughly 1 in |
|---|---|---|
| Mil-Spec (blue) | 79.92% | 1.25 |
| Restricted (purple) | 15.98% | 6.3 |
| Classified (pink) | 3.20% | 31 |
| Covert (red) | 0.64% | 156 |
| Rare Special Item (knife/gloves) | 0.26% | 385 |
Each item also has a 10% chance to be StatTrak in cases that carry StatTrak versions. Valve published these odds in 2017 (to comply with disclosure rules in China) and they're the only official figures. Within a tier, skins are generally treated as equally likely. Valve hasn't published a per-skin breakdown.
Case opening EV calculator (Valve's published rarity odds)
Odds are fixed to the rarity odds Valve published for CS:GO cases in 2017 (shown in the table above). You type in the average market value you'd expect per tier for your case. Nothing here is pre-filled with prices.
| Tier | Odds | Your average value per item ($) |
|---|---|---|
| Mil-Spec (blue) | 79.92% | |
| Restricted (purple) | 15.98% | |
| Classified (pink) | 3.20% | |
| Covert (red) | 0.64% | |
| Rare Special (knife/gloves) | 0.26% |
What EV means
EV (expected value) is the average value you'd get per opening over a huge number of openings. If a case costs $3.50 to open (key + case) and its EV is $1.80, you lose about $1.70 per opening on average. You might hit a knife on opening one, or never in 1,000. EV tells you the price of the entertainment, not the result of your next click.
Why EV is usually negative
- Keys cost $2.49 in the US (see CS2 key price), and that money goes to Valve, not into items.
- 80% of drops are Mil-Spec items typically worth a fraction of the key.
- Selling costs about 13% of the buyer's price on Steam.
Try it yourself
Use the free case opening simulator to feel the odds without spending anything, or plan a contract in the trade-up calculator.
If you still want to open
Opening is entertainment, so set a budget. If you're 18+, our two picks give free cases with code FREECASES4U, which is the only positive-EV opening there is: free. Compare them on case opening sites, and read the case opening guide. Play responsibly.