Elo Rating Calculator

The Elo rating system calculates relative skill levels in two-player games such as chess, football, or tennis. Created by Arpad Elo, it predicts match outcomes and adjusts ratings based on results

The calculator uses the standard published formula for elo rating. Results are accurate to the precision of the inputs you provide. For financial, medical, or legal decisions, always verify with a qualified professional.

This calculator works with inches. You can enter values in the units shown — the calculator handles all conversions internally.

The core formula is: Expected Score: E_A = 1 / (1 + 10^((R_B − R_A) / 400)). Each step in the calculation is shown so you can verify the result manually.