EloCalculatorNET

ELO calculation library in .NET

Supports heads up, team and multiplayer calculations

Installing EloCalculatorNET

You can install EloCalculatorNET with NuGet:

Install-Package EloCalculatorNET

Or via the .NET Core CLI:

dotnet add package EloCalculatorNET

Two player scenario

Create and calculate match between two players

• Player 1 has 1200 rating and wins
• Player 2 has 1320 rating and loses
• Get the ELO rating difference for each player

var match = new EloMatch();
var player1Identifier = match.AddPlayer(1200, true);
var player2Identifier = match.AddPlayer(1320, false);
var result = match.Calculate();

int player1EloDifference = result.GetRatingDifference(player1Identifier);
int player2EloDifference = result.GetRatingDifference(player2Identifier);

Three player scenario

Create a match between three players

• Player 1 has 1280 rating and places 1st
• Player 2 has 1300 rating and places 2nd
• Player 3 has 1220 rating and places 3rd
• Get the new ELO rating for each player

var match = new EloMatch();
var player1Identifier = match.AddPlayer(1280, 1);
var player2Identifier = match.AddPlayer(1300, 2);
var player3Identifier = match.AddPlayer(1220, 3);
var result = match.Calculate();

int player1NewRating = result.GetRatingAfter(player1Identifier);
int player2NewRating = result.GetRatingAfter(player2Identifier);
int player3NewRating = result.GetRatingAfter(player3Identifier);

The calculations is based on:

• Player 1 won Player 2 and Player 3
• Player 2 won Player 3 and lost to Player 1
• Player 3 lost to Player 1 and Player 2

Ten player scenario

• All players have 1200 ELO
• Only one player wins (the first one)
• Write out rating before and after for every player

var teams = new List<EloTeam>();

for (var i = 0; i < 10; i++)
teams.Add(new EloTeam(1200, i == 0));

var result = new EloMatch(teams).Calculate();

foreach (var ir in result.GetResults())
Console.WriteLine($"{ir.PlayerIdentifier}, rating before: {ir.RatingBefore}, rating after: {ir.RatingAfter}");

This is calculated as if the first Player won all, and every other player drew.

Two versus two scenario

• Team 1 consists of Player 1 with 1230 ELO and Player 2 with 1260 ELO
• Team 2 consists of Player 3 with 1120 ELO and Player 4 with 1410 ELO
• Team 1 wins Team 2
• Get results for each team and print out rating difference for each individual

var match = new EloMatch();
var team1 = match.AddTeam(new EloTeam(true));
match.AddPlayerToTeam(team1, 1230);
match.AddPlayerToTeam(team1, 1260);
var team2 = match.AddTeam(new EloTeam(false));
match.AddPlayerToTeam(team2, 1120);
match.AddPlayerToTeam(team2, 1410);
var result = match.Calculate();

foreach (var ir in result.GetResults(team1))
Console.WriteLine($"Team 1 - Player: {ir.PlayerIdentifier}, Rating difference: {ir.RatingDifference}");

foreach (var ir in result.GetResults(team2))
Console.WriteLine($"Team 2 - Player: {ir.PlayerIdentifier}, Rating difference: {ir.RatingDifference}");

Each team has a rating which is an average of the team members.

Team 1 has a rating of 1245 ((1230+1260)/2)

Team 2 has a rating of 1265 ((1120+1410)/2)

Get expected score between two ratings

Say you have two players, one with 1460 ELO and another with 1130 ELO, and want to know the likelihood of one winning another.

var expectedScore = new EloRating(1460).ExpectedScoreAgainst(1130);

This returns a float number and in this specific scenario the value is 0.8698499 meaning the higher ranked player is estimated to win 87% of encounters.