Provably Fair Calculator

Our Provably Fair Calculator & Tracker lets you verify any crypto casino bet in seconds. Simply enter your server seed, client seed and nonce, and our own verification tool recreates the exact result for Crash, Dice, Limbo, Mines, Plinko, Keno and Wheel games so you can independently confirm the outcome of the game you played was, indeed, fair.

Our provably fair verifier works with games from Stake, BC.Game, Rainbet and every other major provably fair casino, and it is completely free to use. Plus, alongside our calculator, the live tracker shows verified bets, the biggest Crash and Limbo multipliers of the day, and the most-played provably fair games across supported casinos in real time. 

Every calculation runs entirely in your browser, too, so nothing you enter is uploaded, logged, or stored: your seeds never leave your device.

What Is Provably Fair?

Provably fair is a cryptographic system that lets you check the outcome of every bet yourself, with verifiable mathematics you can physically check, rather than simply having to rely on a casino or software provider.

That means that, instead of relying on a testing lab's certificate, which is the way pretty much every traditional online casino works, a provably fair casino locks in its randomness before you even bet. It then reveals the code and mathematics after the round has finished, so you can confirm nothing changed in between.

The idea behind it is something called commit-reveal. Before you start a game round, the casino generates a secret random value and shows you a cryptographic fingerprint of it. The fingerprint proves that the value exists and can't be swapped later, but the value itself stays hidden, so you can't calculate results in advance.

Once the game round has finished, the fingerprint is then revealed, allowing anyone to check that both fingerprints match. Every provably fair bet has three core things:

- a server seed (the casino's secret)

- a client seed (your secret)

- a nonce (a bet counter)

You simply need to feed the three values into the same formula, and you always get the same result, which is exactly why independent verification is possible. That's exactly what you can do using the tool on this page.

Provably Fair vs Traditional Online Casinos

Traditional online casinos use technology called random number generators. Testing labs like eCOGRA (eCommerce Online Gaming Regulation and Assurance), iTech Labs, and GLI (Gaming Laboratories International) are responsible for auditing these random number generators, checking - and extensively testing, the code behind a game, regardless of whether it’s a video slot, a progressive jackpot, or a blackjack table.

Once they verify there are no backdoors and that the software provider has developed a fair and random game, they issue a certificate which allows the game to then be offered to players for real money.

The system is pretty much perfect, to be honest, but there is no way for you to personally check a single outcome for yourself, so all of the trust lives with the lab. Provably fair technology changes things completely because the commitment happens before every bet, the reveal happens afterwards, and the mathematics in between are public knowledge.

You don't need to trust anyone or take a casino’s or testing lab's word for it. You can re-run the exact calculation yourself on your own device for any bet in the history of the world, well, since the technology existed, at least!

Provably fair technology took off fairly well at crypto casinos. While it didn't quite catch on in the mainstream market like many industry insiders were hoping for, a lot of players have now moved towards provably fair casino games, especially when playing at offshore sites or those licensed in grey market zones.

How Server Seeds Work

The server seed is simply a long random string of numbers and letters that's generated by the casino before you place any bets. While it is active, it stays secret, because if you could see it, you'd be able to work out what the upcoming result of the round would be. Instead, the casino shows you its SHA-256 hash, a 64-character fingerprint that's unique to that exact seed. 

This is the "commitment" part, and if the casino were to swap the server seed after you've placed a bet, the seed that it eventually reveals would not match the hash you were shown beforehand. It would then become mathematically evident that something shady was going on, and everybody would know the casino was cheating.

Now, when you rotate to a new seed, the old server seed is revealed in full, and that's when you can use verification tools like the one here at CasinoTrackpot to validate every bet that it produced.

How Client Seeds Work

The client seed is simply your half of the randomness. Casinos generally assign you one randomly by default. You can, however, and should, change it to anything you like before betting, as this is just good practice.

Anything works; you can use a random string of numbers, a phrase, or your own dice roll. What matters isn't what it actually is, but that you chose it after the casino's hash was already visible on your screen. 

Why? Because the casino commits to its server seed before it ever knows your client seed. As the final result depends on both values working together, the casino cannot hunt for a server seed that produces a losing game round for you. 

Your input (client seed) only arrives after its commitment is locked in place, and setting a fresh client seed of your own after each rotation ends that loop/round immediately.

What Is a Nonce?

The nonce is simply a counter that begins at 0 or 1 (depending on the online casino you play at). It increases by +1 with each bet you place using the same seed pair.

Now, because the nonce changes every round, each bet produces a different result, even though the seeds themselves stay the same. That’s the reason behind why a single seed pair can cover thousands of bets and why you need the exact nonce, not just the seeds, to verify a bet from your wagering history.

Due to this technology, it also means that the outcome sequence is fixed the moment the seeds are set: nonce 47, for example, always produces the same result for a given seed pair, regardless of whether you wager €1, €10,000, or €100,000,000. 

SHA-256, Explained Simply

SHA-256 is the hash function behind the commitment step, and it takes any input and produces a fixed 64-character output, with three main properties that matter. The same input always produces the same output, so even changing just one character of the input would totally change the output, and that cannot be reversed.

For example, if we look at an example. The SHA-256 hash of "hello" begins 2cf24dba, while the hash of "Hello", just one capital letter changed, begins 185f8db3. One tiny change produces entirely different results, and that’s the entire point: it’s physically, technologically, and mathematically impossible to “cheat” it.

What's so clever about provably fair technology is that seeing the hash in advance tells you nothing about the server seed hiding behind it. It's only once the seed is eventually revealed that you can run it through a SHA-256 and confirm that it produces the actual fingerprint shown before you place the bet. If even one character changes, the whole hash does too.

What HMAC-SHA256 Does

HMAC-SHA256 is where things get slightly more complex; the seeds and nonce actually become the game result, and it’s essentially a keyed version of SHA-256. This means that the server seed acts as the key, while the client seed and nonce form the message. 

The output it then produces is a very long string of hexadecimal characters that looks random, but this output is entirely determined by the inputs.

Those characters are then converted into the numbers the game needs. In Dice, for example, it would decide the roll. In a Crash game, it would determine the multiplier, while in Mines, it would set the mine positions on the grid.

Pretty much every legitimate casino that offers provably fair games documents its exact conversion method, and our calculator above mirrors them exactly, too. The result you see here at CasinoTrackpot matches what the casino's own verification tool will show you as well, but, of course, it’s always better to rely on independent third-party tools than the casino’s.

What Is Seed Rotation?

You cannot verify bets made on your current server seed, because only its hash is visible while the seed is active. Verification unlocks when you rotate. Once you rotate your seed, two things happen at the same time. First, the old server seed is revealed in full, and it then commits the casino to a new hashed seed for the next game round(s). Every bet from the old pair is then instantly verifiable.

Rotation is also your own “control lever”, if you like. The casino doesn’t choose when its seed gets exposed, because you can force the reveal at any time (once the game round ends), which is exactly why this technology is so foolproof for online gambling.

As a general rule of thumb, you should rotate your seed whenever you want to check the results and set yourself a new client seed at the same time. There’s no cost to rotating, and doing so frequently means shorter, easier-to-verify bet histories, too!

How Verification Works Game by Game

The commit-and-reveal system is the same no matter where you play, but each game turns the HMAC-SHA256 output into a result in its own way. Here is what our calculator recreates for each:

1. Crash: The vast majority of Crash games draw from a pre-generated chain of hashes, salted with a public Bitcoin block hash, rather than per-bet seed pairs. This means that each entry in the chain converts into that round's multiplier, so it’s decided well in advance of any bets being placed. Enter the game hash, and the calculator returns the crash point.
2. Dice/Limbo: This is the easiest type simply because the first bytes of the HMAC output convert to a single number: a roll between 0 and 100 in Dice or a result multiplier in Limbo. You just need to have one seed trio, one number, and that’s it; you can check instantly.
3. Mines: Here, the output bytes drive a shuffle that decides which of the (usually) 25 tiles have mines hidden beneath. Our calculator rebuilds the full grid, so you can see every mine position for that nonce, even for tiles you never clicked!
4. Plinko: In Plinko, every row of pegs gets its own slice of the output, and it’s this that determines whether the ball falls left or right. Our calculator then retraces the complete path and the multiplier segment it ends up landing inside.
5. Keno: Successive bytes are used to draw numbers from the board without any repeats, which makes it fairly easy to recreate the exact set of numbers the game ended up revealing.
6. Wheel: In wheel-based provably fair games, a single value is assigned to a random segment of the wheel, so the verification check is simply making sure the slice that was pre-determined to hit did indeed hit.

How to Verify a Bet, Step by Step

Verifying takes under a minute once you know what to actually do:

1. Rotate your seed pair in the casino's fairness or provably fair settings. This reveals the server seed used for your previous bets.
2. Copy the revealed server seed, your client seed and the nonce of the bet you want to check. (You’ll find the nonce listed in each bet’s details panel.)
3. Paste all three into the calculator above or at the casino you’re playing at, and choose the correct game and casino.
4. The calculator recreates the result from your inputs and hashes the revealed server seed, allowing you to match it against the original commitment.
5. If both seeds match, the bet was, indeed, provably fair. If either does not, something is wrong, and you are holding literal evidence of it!

Provably Fair FAQ

What is provably fair?

Provably fair is a verification system used in many crypto casinos where the site commits to its randomness with a SHA-256 hash before you bet and reveals the original value afterwards. That lets you recalculate any result yourself and confirm it was 100% fair and not manipulated.

Is provably fair legit?

Yes, in the sense that results cannot be changed or modified once the seed hash has been shown. It proves outcome integrity, though, so don’t forget that there’s still a house edge in play on all provably fair games. 

Can casinos cheat?

Not on verified bets without breaking the maths, a changed server seed will not match its committed hash, and that mismatch is provable evidence anyone can reproduce. They may get away with it for a couple of days, but soon enough word would catch on, and everybody would simply stop playing there.

How do I verify a Stake bet?

Open Stake's fairness settings and rotate your seed pair; you cannot check bets on an active seed, so you need to do the rotation side of things first. Once it’s revealed, simply copy the server seed, your client seed, and the bet's nonce from your bet details, then enter all three into the calculator above with the correct game selected.

What is a client seed?

The client seed is the player-controlled half of the randomness. You can edit it at any time before betting, and doing so guarantees the casino could not have chosen its server seed with your input already known. You can set a new one every minute, every hour, or every day, it’s up to you!

What is a nonce?

A nonce is the counter that increases by one with each bet on the same seed pair. It’s what helps to make every single bet/game round unique, and it’s also why you need the nonce and the seeds to verify a specific bet.

Can provably fair predict results?

No, 'provably fair' means the game is... well, fair, but you cannot use it to manipulate the game or gain an unfair advantage.

Does provably fair affect RTP?

No. Provably fair allows you to make sure that the game’s round was fair and random, but the RTP is literally built into the game, and that can’t be overcome; if it could, casinos would be out of business in minutes!