Free odds converter
Decimal, fractional and American — bidirectional, real-time, with the implied probability shown.
Odds Converter
betcalc365.com/oddsconverterHow to convert betting odds
Type a value into any of the three input boxes — decimal, fractional or American. The other two update instantly with the equivalent prices, and the implied probability card below shows the bookmaker's view of the underlying chance, as both a percentage and a visual bar. The Common Odds quick-pick chips load standard UK prices into all three fields with one tap — handy as a sanity check on whether your typed value reads right.
What the three odds formats actually mean
All three formats encode the same number: the bookmaker's view of how likely an outcome is, expressed differently for different audiences. Decimal is the modern standard everywhere except the UK retail high street — multiply the price by your stake to see total return (a £10 bet at 2.50 returns £25). Fractional is the UK pub-and-paper tradition: the numerator is profit per units of the denominator (5/2 means £5 profit per £2 staked). American is the US sportsbook format: positive numbers show profit per $100 staked, negative numbers show the stake needed to win $100.
The conversion maths is fixed and exact — no rounding, no operator-specific tweak. What varies is the bookmaker's margin baked into the price they actually offer you, which is what bookmaker pricing actually reveals about probability — the full cornerstone reference covers it.
Common UK odds at a glance
Every price a UK punter routinely encounters, in all three formats, with the implied probability worked out.
| Fractional | Decimal | American | Implied probability |
|---|---|---|---|
| Evens (1/1) | 2.00 | +100 | 50.00% |
| 6/4 | 2.50 | +150 | 40.00% |
| 7/4 | 2.75 | +175 | 36.36% |
| 2/1 | 3.00 | +200 | 33.33% |
| 5/2 | 3.50 | +250 | 28.57% |
| 3/1 | 4.00 | +300 | 25.00% |
| 7/2 | 4.50 | +350 | 22.22% |
| 4/1 | 5.00 | +400 | 20.00% |
| 9/2 | 5.50 | +450 | 18.18% |
| 5/1 | 6.00 | +500 | 16.67% |
| 10/1 | 11.00 | +1000 | 9.09% |
| 20/1 | 21.00 | +2000 | 4.76% |
Related tools and guides
- Betting Calculator — accumulator, system bets, lay, free bet, arbitrage modes in one tabbed interface.
- Golf Dead Heat Calculator — Top 5 through Top 40 finish markets, every tie configuration.
- How to read betting odds — the foundations guide, plain-English explainer.
- How to use the odds converter — walkthrough of every feature on this page.
- Blog — strategy notes, calculator walkthroughs, the cornerstone maths reference.