Betting Odds Converter – instantly switch between decimal, American, fractional odds and their implied probability
What does an odds converter do?
An odds converter is a fast, error‑free way to translate betting odds between the three main formats—decimal, American (moneyline) and fractional—while also displaying the implied probability behind every price. It saves time, removes manual mistakes and lets you compare lines from different bookmakers on one common scale.
Key odds formats explained
| Format | Example | How to read it |
|---|---|---|
| Decimal | 2.10 | Multiply your stake by the number to get the total return (stake × odds). |
| American | +110 | A positive figure shows profit on a €100 stake; a negative figure shows what you must risk to win €100. |
| Fractional | 11/10 | The first number is potential profit, the second is the stake required. |
| Implied Probability | 47.62 % | Indicates how often the bet must win to break even at this price. |
Example: A decimal price of 2.10 carries an implied probability of 100 ÷ 2.10 = 47.62 %.
Why convert odds at all?
- Hunt arbitrage opportunities – line up prices from multiple sportsbooks, convert them to one format and locate risk‑free combinations.
- Spot value bets – compare a bookmaker’s implied probability with your own projections; if the book’s number is lower, the price may offer positive EV.
- Feed other betting tools – many strategies (Kelly criterion, Poisson models, EV calculators) require decimal odds, so conversion is essential.
How to use our calculator
- Enter a number into any field (except fractional, which requires the “x/y” format).
- Watch the other boxes update instantly—no extra clicks, no spreadsheets.
- Act on the insight: compare the converted price to rival books or plug it straight into your valuation model.
Tip: If the implied probability after conversion is below your own estimate, the market may be mis‑priced in your favour.
Quick‑reference formulas
- Decimal → Probability (%):
100 ÷ decimal odds - American (+):
100 ÷ (american + 100) × 100 % - American (–):
american ÷ (american – 100) × 100 % - Fractional a/b → Decimal:
(a ÷ b) + 1
The calculator handles these automatically, but advanced users may want them for manual checks.
FAQ
How do I convert American odds to decimal?
Simply type the American price (with its + or – sign) into the calculator; decimal and probability values appear instantly.
Is implied probability the “true” probability?
Not exactly. It still contains the bookmaker’s margin (the vig), so the true fair probability is slightly lower.
Can I use this tool for live betting?
Yes. Update in‑play odds on the fly to see if a live line offers value compared with your real‑time model.