The Banzhaf Index Calculator is a valuable tool for calculating a player’s power in a voting system or coalition game, represented as a percentage.

By knowing how often a player is critical in winning coalitions, this calculator provides insights into their influence over decisions. This is especially useful in political science, economics, and game theory.

**How to use the Calculator:**

- Enter any two of the following values:
**Number of Winning Coalitions a Player is Part of**
**Total Number of Winning Coalitions in the Game**
**Banzhaf Index (%)**

- The calculator will compute the missing value based on the provided inputs.
- Click
**Calculate** to get the result or **Reset** to clear the fields.

**Solved Calculations**

**Example 1**

**Step** |
**Calculation** |

**Winning Coalitions a Player is Part of** |
15 |

**Total Winning Coalitions** |
50 |

**Banzhaf Index (%)** |
(to be calculated) |

**Calculation** |
(15 / 50) × 100 = **30%** |

In this example, if a player is part of 15 out of 50 winning coalitions, their Banzhaf Index is calculated to be 30%.

**Example 2**

**Step** |
**Calculation** |

**Winning Coalitions a Player is Part of** |
10 |

**Banzhaf Index (%)** |
20% |

**Total Winning Coalitions** |
(to be calculated) |

**Calculation** |
10 / (20 / 100) = **50 coalitions** |

Here, with 10 winning coalitions for the player and a Banzhaf Index of 20%, the total number of winning coalitions in the game is calculated to be 50. This calculation provides insights into the player’s proportional power in decision-making processes.