Rock Paper Scissors Simulator – Play, Match, and Simulate
Rock Paper Scissors is one of the oldest and most universally recognized games for making a fair, unbiased decision between two people. This Rock Paper Scissors Simulator brings the classic hand game online, letting you play a quick round against the computer, contest a full Best-of-N match, or instantly run a bulk simulation of thousands of rounds to explore the underlying probability.
How the Game Works
The rules never change: Rock beats Scissors, Scissors beats Paper, and Paper beats Rock. Whenever both sides choose the same option, the round is a tie and nobody scores. Every computer move in this simulator is generated using a true random number source (crypto.getRandomValues, with a Math.random() fallback), so results are unpredictable and statistically fair — exactly like flipping a coin or rolling a die.
Single Round vs. Best of N
In Single Round mode, pick your move and see the computer's choice and the outcome revealed instantly, with your running score and win streak updated after every play. In Best of N mode, you play a full match made of an odd number of rounds (3 by default, adjustable up to 99). Ties are automatically replayed without counting toward the total, and the match ends the moment either side reaches a majority of the wins — just like a real tournament bracket.
Simulating Thousands of Rounds
Curious about the math behind the game? Switch to Simulate Multiple Rounds mode to instantly play a large batch of fully randomized rounds — both the "player" and computer choices are randomized — and see the resulting Win, Lose, and Tie percentages. Because each of the three choices has an exactly 1/3 chance of beating, losing to, or tying any other choice, running enough rounds will show the percentages converge toward roughly 33.3% each, a nice hands-on demonstration of the law of large numbers.
Weighted Opponent Mode
For a more advanced probability exercise, enable Weighted mode and set custom percentages for how often the computer picks Rock, Paper, or Scissors. Your values are automatically normalized to total 100%, letting you experiment with a biased opponent and observe how the win/lose/tie distribution shifts away from the fair 1/3 split.
Beyond the Game
This tool doubles as a lightweight, unbiased decision-maker or tiebreaker — useful for settling a friendly dispute, picking who goes first, or just enjoying a nostalgic game powered by genuinely random outcomes. Your score, streak, and round history are tracked for the current session only and can be copied or exported at any time; nothing is sent to a server.