What does provably fair mean?

It means you can prove, after the fact, that a result was fixed before you bet. The casino shows a hash of its secret server seed in advance; once the seed is revealed, you can confirm the hash and recalculate every roll.

Do I need to change my client seed?

You do not have to, but it is good practice. Setting your own client seed means the casino could not have prepared the sequence of rolls, because part of the input came from you.

Why can I not verify the current seed?

Because the server seed is still secret. If it were visible, you could calculate the next roll before betting. You verify a seed pair after you rotate it and the casino reveals the old server seed.

Does provably fair mean I will win more?

No. It proves the rolls were not manipulated. The house edge is built into the payouts and applies to every roll, fair or not.

Is every dice game provably fair?

No. In-house crypto dice games usually are. Dice-themed games from outside studios are normally certified by a testing lab instead and cannot be verified by the player.

By: The BestCryptoDiceGames desk
Desk: Dice odds and casino terms
Updated: 18 September 2026

The game · Fairness

Provably fair dice: how to check a roll yourself

Provably fair dice lets you prove the casino fixed its secret before you bet and could not change the result afterwards. Here is how the seeds work, a worked example you can repeat, and what a successful check does and does not prove.

The promise of provably fair dice is simple: you do not have to trust the casino, because you can check it. Every roll is calculated from inputs that are locked before you bet, and after the fact you can recalculate the roll yourself. This page shows how that works, with a real calculation you can repeat, and explains exactly what a successful check proves.

The three inputs

Every provably fair dice roll comes from three pieces of data:

Input	Who sets it	When you can see it
Server seed	The casino	Only as a hash while in use; in full after you rotate
Client seed	You (or a random default)	Always
Nonce	The game, counting your bets	Always

The trick is the hash. Before you place a single bet, the casino shows you the SHA-256 hash of its server seed. A hash works in one direction: it is easy to compute from the seed and practically impossible to reverse. Once the casino has shown you the hash, it cannot swap the seed for another one without the hash changing. It has committed.

How the roll is calculated

The exact formula varies by site and is published in each game's fairness page. A common implementation, the one used by Stake-style originals, works like this:

Take the message client seed:nonce:0.
Compute HMAC-SHA256 of that message, using the server seed as the key.
Take the first four bytes of the result, each a number from 0 to 255.
Turn them into a fraction between 0 and 1: byte1/256 + byte2/256² + byte3/256³ + byte4/256⁴.
Multiply by 10,001, round down, and divide by 100. That gives a roll from 0.00 to 100.00.

Other sites use a different step 4 or 5, for example reading hexadecimal characters until they find a value under a million. The principle is always the same: fixed inputs in, one deterministic number out.

A worked example you can repeat

Here is a real calculation with made-up seeds, so you can run it in any HMAC-SHA256 tool and get the same numbers.

Server seed: a3f1c07e5d9b2e48f6a1d3c5b7e9f0a2c4e6a8b0d2f4a6c8e0b2d4f6a8c0e2f4
Hash shown before betting (SHA-256 of the server seed): e7c198194a805b40270d38fb8b0b264c5436c8d917aa30bcf75290f790835cab
Client seed: myluckyseed

Nonce	HMAC begins with	First four bytes	Fraction	Roll
0	91fbe79c…	145, 251, 231, 156	0.570250	57.03
1	e4a2b690…	228, 162, 182, 144	0.893108	89.31
2	5cd5fe28…	92, 213, 254, 40	0.362640	36.26

If you bet roll under 49.50 on these three nonces, you lose, lose, win. Nothing about your bet changes the roll: the target only decides whether the number counts as a win.

How to verify your own rolls

On a real site the steps are:

Before playing, open the fairness panel and note the hashed server seed. Set a client seed of your own if you like.
Play as normal. Each bet's nonce is shown in your bet history.
Rotate the seed pair in the fairness panel when you finish. The casino reveals the old server seed in full and shows the hash of a new one.
Check the hash. Compute SHA-256 of the revealed server seed and compare it with the hash you noted. They must match exactly.
Recalculate a few rolls. Use the site's verify tool or an independent calculator with the same formula, and compare the rolls with your bet history.

If step 4 fails, the casino changed its seed and the game is not provably fair. If step 5 fails, either the formula you used differs from the site's or the results were altered; check the formula first.

The DuckDice lobby with Original Dice pinned at the top — DuckDice puts its own Original Dice first in the lobby, ahead of slots and sports. It is a dice site that added a casino, not the other way round.

What a successful check proves

A matching hash and matching rolls prove three things:

The server seed existed before your first bet.
The casino did not change it while you played.
Each result follows from the seeds and nonce, not from a decision made after you bet.

It does not prove:

That the game has no edge. The edge is in the payout, 1.98× instead of 2× at 50%, and is fully visible.
That the casino will pay out. Fair rolls and a fair cashier are separate questions. That is why our ranking of crypto dice games scores the licence and the terms, not the game.
That provider games are fair in the same way. Studio games are tested by labs; you cannot verify them seed by seed.

Why your client seed matters

If the casino chose both seeds, in theory it could search for a server seed that produces an unlucky sequence for the default client seed. Setting your own client seed removes that possibility, because the casino commits to its server seed before it knows yours. It takes ten seconds: type any string you like into the client seed field before you start a session.

Sites in our list with provably fair dice

These dice sites run in-house dice with a fairness panel. The ranking and the rules behind it are the same as on the home page.

1 Vave 150% on the first deposit, then 100%, 50% and 25%Withdrawals paid in our real-money test, no documents asked Tested with real money Get bonus
2 Bitsler Dice original in the first row of the lobbyLicence: Curaçao 4.0 Play dice
3 DuckDice Original Dice pinned first in the lobbyCoins: BCH · BTC · DASH · ETH · LTC 4.0 Play dice
4 Rainbet Dice among the Rainbet originalsCoins: BTC · ETH · LTC · XRP · SOL 4.0 Play dice
5 Shuffle Dice listed first among the Shuffle gamesCoins: BTC · ETH · LTC · SOL · USDT 3.5 Play dice
6 Stake Stake Dice in the Stake originalsProvably fair games 3.5 Play dice
7 Crypto.Games Dice among its own provably fair gamesCoins: BTC · ETH · USDT · XRP · BNB 3.0 Play dice
8 TrustDice Dice original and a weekly dice wager contestCashier steps walked through on a real account, May 2026 3.0 Play dice
9 Primedice Dice-only site, sister brand of StakeProvably fair games 2.5 Play dice
10 Flush Dice in the Flush originalsCoins: BTC · ETH · BNB · LTC · USDT 2.0 Play dice

Vave is our partner and sits first by agreement, outside the formula; the rest are ordered by stars. Every button opens Vave.

Dice sites whose own dice game publishes seeds you can check after the roll.

Provably fair and responsible play

Knowing the rolls are honest can make dice feel safer than it is. A fair game with a 1% edge still takes about 1% of everything you wager, and it does so at the speed you play. Keep a deposit limit, keep auto-bet on a stop-loss, and read how crypto dice works before you trust any system. If you want the numbers for a particular target, the dice odds calculator has them all.