# Elo Rating Calculator

URL: https://speedycalculator.com/calculators/sports/elo-rating/
Last updated: 2026-10-25

> The Elo calculator predicts the expected score between two players from their ratings and updates their ratings after a win, draw or loss, as used in chess and many games.

## Inputs

- Your rating
- Opponent rating
- Result
- K-factor

## Results

- Expected score
- New rating
- Change

## Formula

```
Expected = 1 ÷ (1 + 10^((R_b − R_a) ÷ 400))
New rating = R_a + K × (score − expected)
```

## Explanation

A 400-point rating gap means the stronger player is expected to score about 91%.

### How to use the Elo Rating Calculator

- **Your rating**
- **Opponent rating**
- **Result**
- **K-factor**

Results update as you type, and every field accepts the units shown in its menu.

### How it works

The expected score comes from the rating difference; the rating moves by K times the surprise.

### Inputs explained

FieldWhat to enterYour ratingA numberOpponent ratingA numberResultChoose one: Win, Draw, LossK-factorA number

### What each result means

- **Expected score** = 1÷(1 + 10^(([Opponent rating] - [Your rating])÷400))
- **New rating** = [Your rating] + [K-factor]×([Result] - [Expected score])
- **Change** = [K-factor]×([Result] - [Expected score])

### Example values

How the main result changes when **Your rating** changes and everything else stays at the example values above:

Your ratingNew rating8008201,2001,2191,6001,6132,0002,0032,4002,4003,2003,200

## Worked example

Inputs — Your rating: 1,600; Opponent rating: 1,700; Result: Win; K-factor: 20.

Results — Expected score = 0.36; **New rating = 1,613**; Change = 12.8.

## FAQ

**What K-factor should I use?**
FIDE uses 40 for new players, 20 for most players and 10 for players above 2400.

**Why does beating a stronger player give more points?**
Your result exceeded expectations by more.

**What formula does the Elo Rating Calculator use?**
Expected = 1 ÷ (1 + 10^((R_b − R_a) ÷ 400)).