What is a house edge?
The house edge is the share of each bet a game keeps on average. A common definition is the casino's profit as a percentage of the player's original bet. Source
If a game has a 2.70% edge, you lose 2.7 cents of every dollar you bet, on average, over a long run. Any single bet can win or lose. The edge shows up over many bets, and it never goes away.
This calculator covers four game types that are common on skin gambling sites: crash, roulette, coinflip and upgrader. Enter the house edge the site states, your bet and your target, and it shows your real win chance and what you lose on average.
The calculator starts at 2.70%, the edge of single-zero roulette. With 37 pockets and a 35 to 1 payout on one number, the house keeps 1/37 of each bet on average. Source It is a well-known reference game, not the edge of any CS2 site, so type the edge the site states. For a longer explanation with more examples, read house edge explained.
How is the win chance calculated?
Every game here works the same way underneath. If a bet pays m times your stake, a fair game would give you a win chance of 1 / m. A game with a house edge h gives you a bit less than that:
win chance = (1 - h) / m
Your average return per bet is the win chance times the payout. That is (1 - h) / m × m = 1 - h. So you get back 1 - h of each bet on average, and you lose h. This is why the expected loss is the same no matter which target you pick.
| Game | Win chance | Expected loss per bet |
|---|---|---|
Crash, cash out at m | (1 - h) / m | h × bet |
Upgrader at multiplier m | (1 - h) / m | h × bet |
| Coinflip at 2x | (1 - h) / 2 | h × bet |
Roulette color, s of N slots, pays p | s / N | (1 - s / N × p) × bet |
How does the crash formula work?
In crash, a multiplier climbs from 1x until it "crashes" at a random point. You win if you cash out before the crash. With a house edge h, the chance that the crash point reaches at least m is:
P(reach m) = (1 - h) / m
At a 2.70% edge, the chance to reach 2x is 0.973 / 2 = 48.65%. The chance to reach 10x is 0.973 / 10 = 9.73%. A fair game would give 50% and 10%.
How does roulette work here?
Skin site roulette usually has a small wheel with a few colors, and each color pays a fixed multiple. Here the house edge is not an input. It comes from the wheel itself: how many slots each color has and what it pays.
The calculator starts with a single-zero roulette wheel of 37 slots: 18 red and 18 black that pay 2x, and 1 green that pays 36x (35 to 1 plus your bet). Source It is a reference wheel, not the wheel of any CS2 site. Change the slots and payouts to match the site you want to check.
For a color with s slots out of N, paying p times your bet, the edge is 1 - (s / N) × p. On this wheel, red has an 18 in 37 chance (48.65%) and pays 2x, so the edge is 1 - 36/37 = 2.70%. Green has a 1 in 37 chance and pays 36x, which gives the same 2.70% edge.
How do coinflip and upgrader work?
A coinflip pays 2x. At a house edge h, your win chance is (1 - h) / 2. At 2.70% that is 48.65% instead of 50%. Some sites keep a true 50% flip and take a fee from the pot instead. A fee of the same size costs you the same amount on average.
An upgrader lets you bet an item for a chance at a more valuable one. You can set the multiplier and see the chance, or set the chance and see the multiplier. At a 2.70% edge, a 2x upgrade has a 48.65% chance. A 25% chance gets you a 3.89x upgrade instead of the fair 4x.
Worked example: crash at 2x, 100 bets
You bet 1 coin per round in crash and always cash out at 2x. The edge is 2.70%, the tool's starting value.
| Result | Value |
|---|---|
| Win chance per round | 48.65% |
| Expected loss per bet | 0.027 |
| Expected loss per 100 bets | 2.70 |
| Chance to be ahead after 100 bets | 35.5% |
| Chance to lose 10 in a row | 0.13% |
To be ahead after 100 rounds you need at least 51 wins. With a 48.65% chance per round, that happens a bit more than 1 time in 3. So most people who play 100 rounds end up behind, even though every round felt close to a coin toss.
Worked example: chasing a big multiplier
Now you cash out at 10x instead. The win chance drops to 9.73%, and the expected loss is still 0.027 per bet, or 2.70 per 100 bets.
What changes is the swing. The chance to lose 10 rounds in a row jumps to 35.9%. You need 11 wins in 100 rounds to be ahead, and the chance of that is about 38.1%. Big targets feel different, but the average cost is the same. Only the ride gets bumpier.
What is a break-even point?
With any house edge above 0%, there is no break-even target. No multiplier, color or chance setting gets you back to zero on average. The only thing you control is how fast the swings happen.
The "chance to be ahead" number in the tool is about short runs. It shows how often people finish in profit after 100 bets. That number gets smaller the more you play, because the edge keeps taking its share.
Can you check if a roll was fair?
A house edge tells you the average cost, not whether a single roll was honest. For that, many sites use a provably fair system with seeds and hashes. You can recompute a roll with our provably fair verifier, and learn how the system works in how provably fair works.
When should you use this calculator?
Use it before you trust any claim like "50/50 odds" or "huge multipliers." Put in the edge the site states and see what each bet really costs. Compare two sites by their edge alone, since the expected loss per bet is just the edge times your bet.
If you are opening cases instead, the case odds calculator shows the math for real CS2 cases.
This is a math tool, not a tip to play. We do not link to any gambling site from this tool. If gambling stops being fun, visit our responsible gaming page.
