What does provably fair mean?

Provably fair is a method that lets you check a dice roll after the fact. The site shows you a hash of its secret server seed before you bet. Because a hash cannot be reversed, the site cannot change the seed later without the hash changing. This is the same idea as sealing a result in an envelope before you play.

How do seeds work?

Three inputs decide each roll: the server seed, the client seed and the nonce.

  • Server seed. A secret random string the site creates. You see only its hash until the seed is rotated.
  • Client seed. A string you can set yourself. It stops the site from choosing every input.
  • Nonce. A bet counter. It rises by one each bet, so the same seeds give a different roll every time.

The site combines them with a fixed formula to produce a number from 0.00 to 100.00. That number is your roll, as explained in how a CS:GO dice game works.

  1. Step 1: Server seed hash shown

    Before you bet, the site shows a hash of its secret server seed. The seed itself stays hidden.

  2. Step 2: Client seed and nonce

    You set a client seed. The nonce counts your bets, so every roll uses a new number.

  3. Step 3: Roll

    The site combines server seed, client seed and nonce to produce the roll.

  4. Step 4: Server seed revealed

    When the seed is rotated, the site reveals the old server seed.

  5. Step 5: Verify hash

    You hash the revealed seed, compare it with the hash from step 1, then recompute the roll.

Provably fair proves that a roll was not altered after the fact. It is not a safety or licence rating.

How do I verify a roll?

You verify a roll by repeating the site’s calculation yourself. The exact steps differ between sites, so read each site’s provably fair page. In general:

  1. Before you bet, save the server seed hash the site shows.
  2. Set or note your client seed, and note the nonce of the bet you want to check.
  3. Rotate the seed so the site reveals the old server seed.
  4. Hash the revealed server seed and check that it equals the hash you saved.
  5. Run the site’s formula on server seed, client seed and nonce. The result should match your roll.

One documented example uses SHA-256 of server_seed|client_seed|nonce. That is a single operator’s method as described in a third-party review, not a universal standard. CSGO500, for example, documents SHA-256 with a daily global secret and a round number for its in-house games, which is a different design. Always follow the method on the site you are checking.

Can a provably fair site still be unsafe?

Yes. Provably fair proves that a roll was not changed after you bet. It says nothing about whether the operator is licensed, whether it pays withdrawals, or whether its terms are fair. A site can run honest rolls and still block your cashout.

That is why we score fairness as one of six criteria and not the only one. See the methodology for the weights. For the other checks to make, read how to choose a safe CS:GO dice site.

Why change the client seed?

Changing your client seed means you contribute part of the input. It also starts a clean record for the bets you want to check. Rotating the server seed is what makes the old seed available for verification, so rotate it before you try to verify. If a site gives you no way to set a seed or to see past seeds, its fairness claim is hard to check.

Does it change the odds?

No. Provably fair does not change the win chance or the house edge. Those are set by the multiplier formula described in CS:GO dice house edge, RTP and multipliers. A fair roll can still be a losing roll, and over many bets the house edge makes losses more likely than wins in total.

Compare which sites offer fairness tools in our ranking.