Chess Elo Calculator - Calculate Rating Changes

Input Parameters

Your Rating

Opponent's Rating

Your Username

Opponent's Username

Time Control

K-Factor K=20

Result Preview

Win

New: 1500

Draw

New: 1500

Loss

-0

New: 1500

How the Elo Calculation Works

The Elo system calculates expected score from rating difference, then adjusts based on actual result.

E_A = 1 / (1 + 10^{(R_B − R_A) / 400})

R'_A = R_A + K × (S_A − E_A)

R_A, R_B: Current ratings of Player A and Player B
E_A: Expected score for Player A (0 to 1)
S_A: Actual score: Win = 1, Draw = 0.5, Loss = 0

Note: Platforms like Chess.com use the Glicko rating system (with Rating Deviation), not standard Elo with fixed K-factors. Calculations here (Standard Elo) may differ slightly from actual points awarded on those platforms.

Chess ELO Rating Calculator

This ELO calculator functions to estimate your rating point changes (K-Factor, Opponent ELO, Match Result) just like an official FIDE tournament. It is very useful for local tournament organizers or simply calculating potential rating points you might gain.

Standard ELO Calculation

Uses the actual ELO rating system probability formula to ensure precise calculations.

Flexible K-Factor

You can adjust the desired K-Factor. New players or rapid tournaments typically have different multipliers than classical GM tournaments.

Win/Draw/Loss Prediction

Instantly see the comparison of potential rating points gained or lost if you win, draw, or lose against a specific opponent.

Logout

Chess ELO Rating Calculator

Standard ELO Calculation

Flexible K-Factor

Win/Draw/Loss Prediction