By Jay Calder·Updated September 2026

Case Opening EV Calculator

How case EV is calculated

The whole thing is one line of arithmetic, which is why it is worth doing before an open rather than after:

EV = Σ (item value × drop chance)

Add up every possible outcome weighted by how likely it is. That sum is what one open is worth on average. Compare it to the price:

RTP        = EV ÷ case price
house edge = 1 − RTP
expected loss per open = case price − EV

A worked example

A $2.50 case with four outcomes:

Expected value is $2.21 against a $2.50 price — an RTP of 88.2% and a house edge of 11.8%. Every open loses about 29 cents on average. Open a hundred and the expected loss is roughly $29, and the more you open the more reliably that average asserts itself.

Notice where the value sits: over two-thirds of this case's EV is concentrated in outcomes with a combined 6% chance. That is the structural feature of nearly every case — the advertised value lives in the tail, so the median open is far worse than the mean. Most opens return well under the EV, and a handful carry the whole average.

Reading a published drop table

• Check the chances sum to 100%. If they don't, something is missing or wrong, and the EV cannot be trusted. The calculator flags this.
• Use realistic item values. The site's own valuation is often above what you can actually sell or withdraw for. If there is a withdrawal spread or a sell-back penalty, the real EV is lower than the table suggests.
• Watch float and wear. A skin listed at a headline price may drop in a condition worth far less. Where a case lists a range, use the low end.
• Upgrades and battles do not change the edge. They change variance. A case battle is several opens at once, so the expected loss multiplies with the number of cases rather than cancelling out.

Why "expected" does not mean "typical"

Expected value is a long-run average, not a forecast of your session. In the example above the single most likely outcome — a 79% chance — returns $0.40 on a $2.50 open. You lose money on roughly four opens in five, and the arithmetic is held up entirely by a 0.5% knife.

This matters because the mean and the median point in opposite directions. Quoting an 88% RTP makes a case sound close to fair. What a player actually experiences is a long string of losses interrupted rarely, and only sometimes, by a drop that pays for them. Both descriptions are true; only one of them is what happens to most people.

Frequently asked questions

What is a normal RTP for a case site?

Published odds usually work out to 85–95% of case price, so a house edge of 5–15%. For comparison, most casino slots run near 96% and the crypto casino originals covered on this site are often 97–99%. Cases are typically the worse bet on pure edge.

Do case battles improve your odds?

No. A battle is multiple simultaneous opens with a redistribution rule for who keeps the contents. The underlying drop probabilities are unchanged, so the house edge per case opened is identical — you are just taking it faster and with more variance.

Can a provably fair case still be −EV?

Yes, and nearly all of them are. Provably fair proves the draw was not tampered with. It says nothing about whether the payout table is generous. Use the verifier to confirm a result was honest, and this page to work out whether the odds were worth taking in the first place.

Does opening more cases improve my chances of profit?

It does the opposite. With a negative edge, more opens means your realised return converges on the expected loss. A small number of opens has high variance, which is the only way to finish ahead — and also the reason it rarely happens.

See also: the wagering requirement calculator for casino bonuses, and the guide to evaluating case site offers.