PLINKO PROVABLY FAIR VERIFIER

Watch a Plinko ball ricochet down the pyramid and it looks like physics. It is not: on a provably-fair casino the “physics” is a scripted playback of decisions already made by cryptography when your bet registered. That is good news for auditability — a path is just data, and data can be recomputed. Punch in your seeds and this page prints the very same L/R sequence the animation acted out.

Not sure which to choose? See what we recommend for each type of player.

HOW PLINKO PATHS ARE CALCULATED

The tool first checks that SHA-256(revealed server seed) matches the hashed seed you were shown. Then, at Stake and Shuffle (their published game-events pages), Plinko consumes one float per row to decide each bounce:

1. Generate one float per row from the HMAC stream.
2. For each row, floor(float × 2) → 0 = Left, 1 = Right.
3. The landing bucket = the number of Rights (0 = far-left bucket).

Reference drop: seeds some server seed / some client seed at nonce 1 on eight rows bounce R R L L R R R L — five rights, so bucket 5. Row count changes how many floats are read, and risk level changes the prize ladder, but neither changes the arithmetic the verifier replays. Pick your row count (8–16) in the tool.

BC.Game Plinko is different: its open-source verifier (github.com/bcgame-project/verify, plinko.html) uses HMAC-SHA512(serverSeed, "clientSeed:nonce"), turns the 64 bytes into 16 floats and sends the ball right when a float is above 0.5. The tool reproduces that; for boards under 16 rows it reads the first floats, which is our assumption, so compare the path with BC.Game’s own verifier. Roobet and other casinos are not reproduced.

THE BINOMIAL TRUTH ABOUT BUCKETS

Plinko’s payout board is a probability lesson in disguise. Eight fair coin flips generate 2⁸ = 256 equally likely paths, but the paths funnel unevenly into nine buckets: only 1 path in 256 (≈0.4%) reaches each far edge, while 70 of 256 (≈27%) end dead centre — the counts run 1, 8, 28, 56, 70, 56, 28, 8, 1. That is why the monster multipliers live at the rim and the centre pays pennies: the casino prices each bucket against its binomial frequency, shaved by the house margin. When this tool confirms your path was fair, those published frequencies are exactly what you were playing against — no more, no less.

WHAT A PATH CHECK BUYS YOU

Suspicion in Plinko usually sounds like “the ball swerved off the 1000x bucket at the last peg.” The animation genuinely can look that way — but the final peg never decided anything. All eight (or sixteen) bounces were fixed together, before the ball was drawn, by seeds the operator had already committed to. Recomputing the sequence proves the swerve was scripted from the start rather than steered in flight. Pair the check with the Plinko odds calculator to see whether a bucket’s payout is priced fairly against its true frequency, and read our rigging investigation for the wider evidence.