How CS2 case ROI and expected value are calculated
Every case has a fixed drop-odds profile published by Valve in 2017. The CS2 case expected value formula multiplies each tier chance by the average item price in that tier, applies the float-based wear distribution to each skin, and adds the flat 10% StatTrak bonus on non-glove drops. That sum is EV. Divide by the case plus key cost and you have ROI:
Weapon case tier odds
- Mil-Spec79.92%
- Restricted15.98%
- Classified3.2%
- Covert0.64%
- Rare Specialknives and gloves0.26%
Souvenir packages, sticker capsules, autograph capsules, and armory collections each follow their own drop profiles. Full probability analysis for every container type is on the drop rates page.
