Hash Roulette: Guess the next Bitcoin block hash
Call the last character of the next block hash.
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Pick a character or a group
You play with chips: they are free (more every hour), you can lose them, and they are never bought, sold or swapped for sats. The weekly rankings pay real sats into your wallet. See the weekly rankings →
One play per market and block: one exact character, letter/number, high/low and even/odd. A play counts only if made at least 30 s before our last check that the block hadn’t been found yet; later plays are refunded.
How to play
- You play with chips, not money. Chips are free: 10,000 when you join and more every hour. You can lose them all, and they are never bought, sold or swapped for sats.
- The round is the next block. Its hash ends in one of 16 characters, each equally likely.
- Exact character pays ×15. Letter (a–f, 6 of 16) pays ×2.55. Number (0–9, 10 of 16) pays ×1.55. High (8–f), low (0–7), even and odd pay ×1.95.
- One play per market and block: one exact character, one of letter/number, one of high/low and one of even/odd.
- Resolved the moment the block is recorded: the hash is final as soon as the block exists.
- A play counts only if it was made at least 30 seconds before our last check that the block hadn’t been found yet; later plays are refunded, so nobody can play once the result is out. If our connection to the network falls behind, plays pause until it catches up.
- If the network replaces a block (a chain reorganisation) before its round is settled, the round is void and every play gets its chips back.
- Every week the rankings pay real sats into the winners’ wallets. Each correct call here counts for “Most correct block calls”, besides chips won and chips played. Paying never gives you chips.
About this game
A Bitcoin block hash is 64 hexadecimal characters (0–9 and a–f). Miners grind through quintillions of hashes until one starts with enough zeros; the end of the winning hash is pure chance.
Hash Roulette turns that last character into a 16-cell board. Nobody can predict or influence it, not even the miner, and anyone can check it on mempool.space the second the block appears.
Can a miner choose how the hash ends?
Not in practice. A miner who threw away a valid block to change one character would lose the whole block reward (several BTC) to move a 1-in-16 outcome.
Is “even” about the character or its value?
Its value: 0, 2, 4, 6, 8, a (10), c (12) and e (14) are even.
Can I buy chips or cash them out?
No. Chips are free play tokens with no money value: they can’t be bought, sold or exchanged for sats. The only sats in the game come from the weekly rankings, paid from the prize pot.
How do the weekly rankings work?
Each week (Monday to Sunday, UTC) your plays count towards several rankings: most chips won, most chips played, most correct block calls and biggest single win. The top places share real sats from the weekly pot.