What does the case EV calculator show?
It shows what one CS2 case opening is worth on average, in dollars, next to what the opening costs you. The cost is the case price plus the key price. The value is the expected value, or EV, of the item that drops.
The table ranks all 42 cases in our item dataset by return. Return is EV divided by cost. A return of 60% means that, on average, every $1 you spend on a case and key gives you 60 cents of items back. Pick any case to see where its value comes from, rarity by rarity.
EV is an average over many openings. It does not tell you what your next case will give you. Most openings give a Mil-Spec item worth a few cents, and a few rare pulls carry the average.
How is case EV calculated?
The formula adds up one line for each rarity:
EV = sum of P(rarity) × average value of the items in that rarity
P(rarity) is the chance of that rarity. The average value is the plain average of the items in that rarity in this case. Then:
Return = EV ÷ (case price + key price)
The chances are the case odds Valve published in 2017, which still apply to CS2 weapon cases. You can see them with their source on our CS2 drop rates page.
| Rarity | Chance per case |
|---|---|
| Mil-Spec (blue) | 79.92% |
| Restricted (purple) | 15.98% |
| Classified (pink) | 3.20% |
| Covert (red) | 0.64% |
| Knife or gloves (gold) | 0.26% |
The five chances add up to 100%, so every opening gives exactly one item.
How is each item priced?
Each item gets one value from Skinport, the only price source we use. We take the lowest listing for each wear the item can have, and average the wears that have a listing. A skin with Factory New at $4, Minimal Wear at $2 and Field-Tested at $1 gets a value of $2.33.
StatTrak is added on top. Valve has not published a StatTrak chance, so we use the 10% figure most players cite. For an item that can be StatTrak, the value is 90% of its normal average plus 10% of its StatTrak average. If there is no StatTrak listing, we use the normal average alone.
Knives and gloves work the same way. Doppler and Gamma Doppler phases share one market name per wear on Skinport, so each finish is counted once, at the lowest listing of any phase. That undervalues rare phases like Ruby or Emerald.
Where do the case and key prices come from?
The case price is the lowest Skinport listing for the case, for example "Fever Case". You can type your own case price for the case you are looking at. If Skinport had no listing for a case in our snapshot, the table shows "No listing" and leaves it out of the ranking. On the 24 Sep 2026 snapshot that was true for 4 cases: Kilowatt, Revolution, Recoil and eSports 2013.
The key price starts at $2.49, the price of a key bought inside the game in USD. Valve shows that price only in the game. We could not find a Valve web page that states it, so our source is a secondary one. Other currencies have their own key price, so change it to match what you pay.
Worked example 1: Fever Case
These numbers come from the 24 Sep 2026 Skinport snapshot, taken at 03:38 UTC.
The Fever Case had a lowest listing of $0.53. With a $2.49 key, one opening costs $3.02.
First, one item. The M4A4 Choppa averaged $0.32 across its wears, and $0.776 as StatTrak. Its value is 0.9 × $0.32 + 0.1 × $0.776 = $0.366.
Then each rarity:
| Rarity | Chance | Average value | Adds to EV |
|---|---|---|---|
| Mil-Spec | 79.92% | $0.276 | $0.221 |
| Restricted | 15.98% | $0.889 | $0.142 |
| Classified | 3.20% | $7.106 | $0.227 |
| Covert | 0.64% | $61.54 | $0.394 |
| Knife or gloves | 0.26% | $228.33 | $0.594 |
| Total EV | $1.578 |
The return is $1.578 ÷ $3.02 = 52.2%. On average you lose about $1.44 per opening before any selling fee. Notice that the 0.26% gold row adds more to EV than any other rarity.
Worked example 2: Prisma Case
Same snapshot, 24 Sep 2026. The Prisma Case had a lowest listing of $1.04, so one opening costs $3.53 with the $2.49 key.
| Rarity | Chance | Average value | Adds to EV |
|---|---|---|---|
| Mil-Spec | 79.92% | $0.787 | $0.629 |
| Restricted | 15.98% | $3.547 | $0.567 |
| Classified | 3.20% | $8.876 | $0.284 |
| Covert | 0.64% | $96.84 | $0.620 |
| Knife or gloves | 0.26% | $346.07 | $0.900 |
| Total EV | $2.999 |
The return is $2.999 ÷ $3.53 = 85.0%. The case costs twice as much as the Fever Case, but its items are worth much more, so the return is higher. Even so, the average opening still loses about 53 cents.
What are the limits of this method?
The calculator is honest about what it does not know. Keep these limits in mind:
- Floats are not uniform in reality. Averaging the wears treats Factory New and Battle-Scarred as equally likely. Real wear odds depend on each skin's float range and how floats are rolled, which Valve does not publish.
- Low-volume items can skew the average. A rare knife with one odd listing can move a whole case. Check the "Items priced" column and open the rarity list in the breakdown.
- Missing prices are skipped. Items with no Skinport listing are left out of their rarity's average, which can push the average up or down.
- Fees are not included. Selling an item on any marketplace costs a fee, so the money you could actually get is lower than EV.
- One marketplace only. All prices come from Skinport. Other sites and the Steam Market price things differently.
- Prices move. The snapshot time is shown under the tool. Case prices can change a lot after a drop pool change. Read how case drop pool changes affect prices for why.
When should you use it?
Use it before you open a case, to see what the average opening gives back. Use it to compare cases if you want a specific collection anyway. It is also a good reality check. Open the same case for free in the case simulator and watch how rarely the gold row actually hits.
To see how many openings you would need for a knife, try the how many cases for a knife calculator. To learn why skins cost what they do, read how CS2 skin prices work. And if you are thinking of cases as an investment, read are CS2 skins a good investment first.
