Bitcoin casino crash games: how the multiplier, edge and hash chain work

A bitcoin casino crash game is a round where a multiplier climbs from 1.00x and stops at a random point, called the bust or crash. Cash out before it stops and you win your stake times the multiplier; still be in when it stops and you lose the stake. This guide explains the maths behind the bust point, how much house edge crash games carry, how the hash chain lets you check a round after it ends, which crypto casinos we review run their own crash, how Aviator differs from in-house versions, and how to size bets so a cold run does not empty your balance. To compare those casinos on payouts, licences and limits, see our ranking of Canadian crypto casinos.

How a crash round works

Every crash game follows the same loop:

1. A short betting window opens. You set a stake in BTC, USDT or another coin the casino takes.
2. You can set an auto cash-out, for example 2.00x, or plan to click cash out by hand.
3. The round starts and the multiplier rises: 1.10x, 1.50x, 2.00x and up.
4. At the bust point the round ends for everyone at once.
5. Anyone who cashed out earlier is paid stake times their cash-out multiplier. Everyone else loses the stake.

Two details matter. First, the round is shared: every player in it sees the same bust point, so the result cannot depend on one player's seed. Second, some rounds bust at 1.00x before the multiplier moves at all, and no cash-out can save those bets. Our glossary entry on the crash game has the short definition.

The maths: how likely is each multiplier?

On a well-built crash game, the chance that the round reaches a multiplier m is:

Chance of reaching m = (1 minus house edge) / m

With a 1% edge, the rate BC.Game publishes for its Crash, that gives:

Multiply the chance by the multiplier and you get 0.99 on every line. That is the point of the formula: whatever cash-out you choose, you get back 99% of what you stake on average. Your target changes how often you win and how big each win is, not the expected cost.

On BC.Game's published formula, about 2 rounds in 100 end at 1.00x. Those instant busts are where the edge comes from: they take every bet in the round, whatever cash-out was set.

What house edge do crash games carry?

The edge depends on the game, so read the casino's own figure:

• In-house crash (originals). BC.Game's formula builds in a 1% edge. Shuffle, for comparison, gives a range of 97.30% to 99.48% RTP across its originals. At 1%, C$1,000 of total bets costs about C$10 on average.
• Studio crash games. Spribe lists a 97% return to player for Aviator, which is a 3% edge. The same C$1,000 of bets costs about C$30.

The edge applies to everything you wager, not to your deposit. Crash rounds are short and auto-bet repeats them without a pause, so volume adds up fast: 500 rounds at C$5 is C$2,500 wagered and about C$25 of expected cost at 1%. Our guide to the best RTP casino games compares that with slots, blackjack and video poker, and our house edge entry explains the term.

How hash-chain fairness works

Dice and Mines use a seed pair per player: your client seed, the casino's hashed server seed and a nonce. Our bitcoin dice guide walks through that check step by step. Crash cannot work that way, because one result has to serve every player in the round. Most crash games use a hash chain instead:

1. The casino generates a secret seed and hashes it with SHA-256, then hashes the result, and repeats, often 10 million times.
2. It publishes the last hash in the chain before any round is played.
3. Rounds use the chain in reverse: the first round uses the second-to-last hash, the next round the one before it, and so on.
4. After each round, the casino reveals that round's hash. Hash it once with SHA-256 and you get the previous round's hash. Because SHA-256 cannot be run backwards, the casino could not have built the chain after seeing any bets.
5. A formula turns each hash into a bust point.

Many casinos also mix in a salt they could not know in advance, such as the hash of a future Bitcoin block, announced before that block is mined. That stops the operator choosing a chain that happens to favour it.

BC.Game publishes its conversion in full. Take the first 13 hexadecimal characters of the round's hash and divide by 2^52 to get a number X between 0 and 1. Compute 99 / (1 minus X), set anything under 100 to 100, round down and divide by 100. Its worked example, a hash starting 6b5124897c3c4, gives X of about 0.4192 and a bust of 1.70x. We ran the same numbers and got the same result.

Checking a round yourself

• Copy the revealed hash from the round history.
• Hash it with any SHA-256 tool and confirm it matches the previous round's hash.
• Apply the casino's published formula, with the salt if it uses one, and compare the result with the bust shown.
• If a casino does not publish its formula or salt, you can only check the chain links, not the bust points.

Which crypto casinos run their own crash game?

These casinos list Crash among their in-house games in our reviews. The scheme column shows what each one documents:

Duelbits, BetFury, Chips.gg, Grailbet, MetaWin, Degen, Legendz, Vegabet, Wild.io and Cashy also list Crash among their provably fair originals; open each casino's fairness page before you rely on a check. Roobet and CasinOK offer crash games without a documented seed system, and 1win runs its own crash titles, such as Lucky Jet, that we treat as standard RNG games.

Aviator vs casino originals

Aviator, made by the studio Spribe, is the best-known crash game, and many crypto casinos carry it next to their own versions. The gameplay is the same: a plane climbs, the multiplier rises, and you cash out before it flies away. The differences are about who runs the game:

• Edge. Spribe lists Aviator at 97% RTP. In-house crash at a casino like BC.Game runs at 99%.
• Fairness check. Aviator has its own seed-based check inside the game, run by Spribe, not by the casino. Originals use the casino's own chain and verifier.
• Where you find it. Our reviews note Aviator in the lobbies of LetsLucky, MagicianBet, Wild.io and Legendz, among others.
• Bonus wagering. Gamdom's terms, for example, exclude its originals and many Aviator titles from bonus wagering. Check game weighting before you play crash with a bonus active.

If the lower edge matters to you, a documented original is the cheaper game. If you prefer a studio game with its own check, Aviator is the standard.

Bankroll limits for crash

No cash-out pattern beats the edge, but you control how fast you lose and how badly a streak hurts:

• Size each bet from a session budget. At 1% to 2% of the session per round, a run of 10 losses costs 10% to 20% of it, not all of it.
• Match the target to your budget. At 10x you miss 10 rounds in a row about 35% of the time. A small balance cannot ride that out at a big stake.
• Do not double after losses. Starting at C$1 and doubling at 2x, ten straight misses cost C$1,023 and the eleventh bet needs C$1,024, all to win back a C$1 profit.
• Set auto cash-out before the round. Clicking by hand invites chasing one more step.
• Cap the number of rounds. Auto-bet with a stop after a set number of rounds or a set loss.
• Check the game rules for a maximum win or profit per round. A very high cash-out can be capped below what the multiplier shows.

Crash is fast, so set a deposit limit before you start. Free help is available from ConnexOntario at 1 866 531-2600 and Jeu: aide et référence at 1 800 461-0140, and our responsible gambling page lists services in every province.

Sources: BC.Game provably fair page, Gamdom Originals, Shuffle provably fair implementation, Shuffle provably fair game events, Gamba provably fair implementation, Thrill Originals, Spribe: Aviator, NIST FIPS 180-4, Secure Hash Standard

The same expected value maths applies to mystery boxes and CS2 cases. See what mystery box sites are and how they work.