Craps Rolls Generator

For those who want to test their betting systems

Last update: October 2021

If you plan to use this to test your betting system idea, see the right and wrong way to test betting systems.   You can also see how these numbers are generated.

Number of come-out rolls:

Number of rolls to generate:



Finished generating, now your browser is writing the results to the window.
This could take several seconds.

Practice craps with fake money (or real money) at Bovada


How the numbers are generated

I wrote the generator in Javascript, telling the computer to pick a random number between 1 and 6, and then another random number between 1 and 6.  The results are pretty much indistinguishable from live casino results.

I used the built-in Math.random() function in Javascript.  In most web browsers (Chrome, Safari, Firefox) Javascript uses an algorithm called Xorshift128+ to generate pseudo-random numbers.  This is way more than adequate for testing betting systems.

Some people hear that computers don't generate “real” random numbers, they generate “pseudo-random numbers” (true), and therefore conclude that computers are inadequate for testing betting systems, and that their systems can beat the real world of a casino even if they can't beat the numbers generated by a computer (completely dead wrong).  For almost all intents and purposes, the numbers generated by Xorshift128+ or any of the other modern algorithms are virtually indistinguishable from real random numbers.  They pass batteries of statistical tests for randomness, including frequency distribution, gaps, and repetition (or lack thereof).  The bottom line is, you can't tell the computer-generated output from the real thing, and there's no statistical difference between live results in a real casino and what you get from the generator.

Of course, you could always just get a pair of dice and roll them a bunch of times.

Related stuff


  • How to play craps.  If you're trying to test your betting system then you know how the game is played, but if you got here by mistake, then here's the primer on how to play.
  • Practice craps.  Bovada's game lets you play with fake money so you can learn the game without risk.
  • Parody instructions for How to Play Craps.  If you thought the “How to Play Craps” article was confusing, try to follow along on this one.
  • The "Come" bet.  I recommend newbies stick to the Pass Line bet, but if you're ready to move on to another bet, this one's also good.
  • The "Don't Pass" bet.  This is an interesting craps bet, but people who play it are often considered pariahs.

Betting Systems

Practice gambling with play money

Before you throw down your hard-earned cash in a casino, PRACTICE FIRST!  Learn the games with play money where it doesn't cost you anything if you lose.  Seriously.

You can play Bovada's games (below) right away without registering for an account.  Most every other online casino makes you give up your email address just to play the fake-money games — ugh.  That's the main reason Bovada is the only online casino that gets advertising space on my site.  (When you see the registration box, you can cancel it and proceed to the game without registering.)

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