Probability To Odds Converter
Enter a probability or odds value and instantly convert between percentage, decimal, fractional, and for/against odds formats.
Input
Enter a value between 0 and 100.
Quick Examples
Enter a value on the left to see all conversions.
Probability
—
As a percentage
Decimal Probability
—
Between 0 and 1
Fractional Odds
—
Win : Lose (e.g. 3/1)
Decimal Odds
—
Total return per unit staked
Odds Ratio (For : Against)
—
Number of ways the event can happen vs. not happen
Common Probability — Odds Reference
| Probability | Fractional | Decimal | For : Against |
|---|---|---|---|
| 10% | 9/1 | 10.00 | 1 : 9 |
| 20% | 4/1 | 5.00 | 1 : 4 |
| 25% | 3/1 | 4.00 | 1 : 3 |
| 33.3% | 2/1 | 3.00 | 1 : 2 |
| 50% | 1/1 | 2.00 | 1 : 1 |
| 66.7% | 1/2 | 1.50 | 2 : 1 |
| 75% | 1/3 | 1.33 | 3 : 1 |
| 80% | 1/4 | 1.25 | 4 : 1 |
| 90% | 1/9 | 1.11 | 9 : 1 |
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Summary
Enter a probability or odds value and instantly convert between percentage, decimal, fractional, and for/against odds formats.
How it works
- Select your input format: probability (%), decimal probability, fractional odds, or decimal odds.
- Type your value into the input field.
- The tool computes all equivalent representations in real time.
- Copy any output field with a single click.
- Use the reference table at the bottom for common probability–odds pairings.
Use cases
- Convert implied probability from bookmaker odds.
- Check the odds ratio for a statistical experiment.
- Translate fractional betting odds into a win probability.
- Verify decimal odds before placing a wager.
- Teach probability concepts using multiple equivalent representations.
- Convert research data between probability and odds ratio formats.
Frequently Asked Questions
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Last updated: 2026-05-23 ·
Reviewed by Nham Vu