Elo 400 Calculator

ELO 400 Scale Formula:

\[ P = \frac{1}{1 + 10^{(R_{opp} - R)/400}} \]

Win Probability (P):

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1. What is the ELO 400 Scale?

The ELO rating system is a method for calculating the relative skill levels of players in competitive games. The 400 scale determines the expected win probability between two players based on their rating difference.

2. How Does the Calculator Work?

The calculator uses the ELO probability formula:

\[ P = \frac{1}{1 + 10^{(R_{opp} - R)/400}} \]

Where:

\( P \) — Win probability (0 to 1)
\( R \) — Your ELO rating
\( R_{opp} \) — Opponent's ELO rating

Explanation: The formula shows that a 400-point rating difference means the higher-rated player has a 10:1 expected win ratio.

3. Importance of ELO Rating

Details: ELO ratings provide a standardized way to compare player skills across different games and competitions, from chess to video games.

4. Using the Calculator

Tips: Enter both players' ELO ratings to calculate the expected win probability. Higher differences result in more lopsided probabilities.

5. Frequently Asked Questions (FAQ)

Q1: Why is it called "400 scale"?
A: Because a 400-point difference corresponds to a 10:1 expected win ratio.

Q2: What's considered a significant ELO difference?
A: 200 points means ~75% expected win rate, 400 points means ~90% expected win rate.

Q3: Can this be used for team ratings?
A: Yes, ELO can be applied to individual players or teams with appropriate adjustments.

Q4: How often should ratings be updated?
A: After each competitive match to maintain accuracy of the rating system.

Q5: What's the K-factor in ELO systems?
A: The K-factor determines how much ratings change after each game (not shown in this calculator).