What is the Elo rating system?
The Elo rating system is a method for estimating a player’s skill level based on match results. Each player is assigned a numerical rating that increases when they win and decreases when they lose.
In LeagueRepublic, Elo ratings update automatically after each recorded game. Ratings reflect a player’s performance against opponents and help estimate the probability of winning future matchups.
Enabling or Disabling Elo Ratings
You can enable or disable Elo ratings in:
Setup > Statistics Setup > Game Formats > Settings
When Elo ratings are enabled, LeagueRepublic automatically calculates player ratings behind the scenes.
Note: There may be a short delay (up to 5 minutes) before ratings update after results are entered.
What Happens When Elo Ratings Are Enabled
When the Elo system is turned on, LeagueRepublic provides several features:
All-time and season ratings displayed on the Stat Leaders page
Win probability predictions shown for upcoming matches
Rating history graphs on player profile pages
Rating adjustments for each game shown on the player page
These tools help leagues track player performance and compare skill levels over time.
How the Elo Rating System Works
Each player starts with a rating.
When two players compete:
If the higher-rated player wins, their rating increases slightly.
If the lower-rated player wins, their rating increases more significantly.
The losing player’s rating decreases.
The rating change depends on:
The difference in the players’ ratings
The expected result of the match
The K-factor, which controls how large rating adjustments can be.
This system means that unexpected results (upsets) lead to larger rating changes.
Example: Elo Rating Calculation
Assume:
Player 1 rating = 1400
Player 2 rating = 1600
K-factor = 32
Step 1 - Calculate the expected outcome
Expected score for Player 1:
1 / (1 + 10^((1600 − 1400) / 400))
This gives Player 1 an expected score of approximately 0.24.
This means Player 1 is expected to win about 24% of the time.
Player 2 therefore has an expected score of 0.76.
Step 2 - Apply the match result
If Player 1 wins the match:
Actual result:
Player 1 = 1
Player 2 = 0
Rating adjustment formula:
Rating change = K × (Actual result − Expected result)
Step 3 - Calculate the rating change
Player 1 adjustment:
32 × (1 - 0.24) = +24
Player 2 adjustment:
32 × (0 - 0.76) = -24
Step 4 - Updated ratings
After the match:
Player 1 rating becomes 1424
Player 2 rating becomes 1576
The larger change occurs because the lower-rated player won an unexpected result.
Elo Ratings for Doubles Matches
For doubles matches, LeagueRepublic calculates the team’s rating using the average Elo rating of both players.
Example:
Team rating =
(Player A rating + Player B rating) ÷ 2
The result is then used to calculate rating adjustments for the match.
Elo Ratings for Larger Teams
Elo ratings are currently calculated for:
Singles matches
Doubles matches
Ratings are not adjusted for triples teams or larger team formats.
Why Use Elo Ratings in a League
Elo ratings help leagues:
Track individual player skill levels
Compare players across teams
Predict likely match outcomes
Display performance trends over time
This can make leaderboards and player statistics more meaningful than simple win–loss records.
Frequently Asked Questions
Do Elo ratings update automatically?
Yes. Once match results are recorded, LeagueRepublic automatically updates player ratings. Updates may take a few minutes to appear.
What is the K-factor?
The K-factor determines how much a player’s rating can change after each game. A higher K-factor means ratings change more quickly.
Why did my rating increase only slightly after a win?
If you beat a lower-rated opponent, the system expected you to win, so the rating change is smaller.
Why did my rating increase a lot after a win?
If you beat a higher-rated opponent, it is considered an upset, so the system increases your rating more significantly.