# Odds to Probability Calculator

URL: https://speedycalculator.com/calculators/statistics/odds/
Last updated: 2026-10-25

> The odds calculator converts betting odds into implied probability and back: fractional odds (5/1), decimal odds (6.0) and American moneyline odds (+500).

## Inputs

- Decimal odds

## Results

- Implied probability
- Fractional odds (x/1)
- American odds

## Formula

```
Decimal odds = 1 + fractional
Implied probability = 1 ÷ decimal odds
```

## Explanation

Bookmakers express the same chance in different formats around the world. Implied probability shows what the odds really say.

### How to use the Odds to Probability Calculator

- **Decimal odds**
- Want to work backwards? Type a value into **Implied probability** and **Decimal odds** is calculated for you.

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

### How it works

Convert any format to decimal odds, then take the reciprocal for the implied probability.

### What each result means

- **Implied probability** = 1÷[Decimal odds]×100
- **Fractional odds (x/1)** = [Decimal odds] - 1

### Example values

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

Decimal oddsImplied probability (%)1.7557.1432.6338.0953.528.5714.3822.8575.2519.048714.286

## Worked example

Inputs — Decimal odds: 3.5.

Results — **Implied probability = 28.571 %**; Fractional odds (x/1) = 2.5; American odds = 250.

## FAQ

**Why do implied probabilities add up to more than 100%?**
The excess is the bookmaker’s margin.

**What does +250 mean?**
A 100 stake wins 250, decimal odds 3.5.

**What formula does the Odds to Probability Calculator use?**
Decimal odds = 1 + fractional.

**Can I work backwards from the result?**
Yes. Type the result you want into Implied probability and the calculator finds the matching decimal odds.