Why Three Formats Exist
The three odds formats — fractional, decimal, and moneyline (American) — co-exist because they were developed independently in different betting traditions and became entrenched at their respective markets. UK sportsbooks display fractional by default, though most allow you to switch. European and Australian books default to decimal. US-licensed books use moneyline. Understanding all three lets you compare prices accurately across platforms, particularly on major international events where multiple operators are pricing the same market.
Fractional Odds (UK Traditional)
Fractional odds express the profit relative to the stake. The numerator is the profit; the denominator is the stake. Reading 5/1 (spoken "five-to-one"): stake £1, win £5, total return £6. Reading 2/5 (spoken "two-to-five"): stake £5, win £2, total return £7. Fractions with a numerator smaller than the denominator are called "odds-on" — the horse or team is considered a favourite.
Converting to implied probability: divide the denominator by the sum of numerator and denominator. For 5/1: 1 ÷ (5+1) = 16.7% implied probability. For 2/5: 5 ÷ (2+5) = 71.4% implied probability.
Decimal Odds (European Standard)
Decimal odds include the stake in the return figure. A decimal price of 6.00 means a £1 stake returns £6.00 total — equivalent to 5/1 fractional. Decimal 1.40 means a £1 stake returns £1.40 total — equivalent to 2/5 fractional.
Converting to implied probability: divide 1 by the decimal odds. For 6.00: 1 ÷ 6.00 = 16.7%. For 1.40: 1 ÷ 1.40 = 71.4%.
Conversion from fractional to decimal: decimal = (numerator ÷ denominator) + 1. For 5/1: (5÷1)+1 = 6.00. For 2/5: (2÷5)+1 = 1.40.
Moneyline / American Odds
American odds are expressed as a positive or negative integer relative to 100. A positive moneyline (+500) shows how much profit a £100 stake returns — so +500 = £500 profit on £100, equivalent to 5/1 fractional or 6.00 decimal. A negative moneyline (-250) shows how much you need to stake to win £100 — so -250 = stake £250 to profit £100, equivalent to 2/5 fractional or 1.40 decimal.
Most UK operators do not display moneyline odds, but you will encounter them when comparing prices on American sites, or on esports platforms such as Midnite that sometimes blend US and European display formats.
Odds Conversion Reference Table
| Fractional | Decimal | Moneyline | Implied prob. |
|---|---|---|---|
| 1/5 | 1.20 | -500 | 83.3% |
| 1/4 | 1.25 | -400 | 80.0% |
| 1/3 | 1.33 | -300 | 75.0% |
| 1/2 | 1.50 | -200 | 66.7% |
| 4/6 | 1.67 | -150 | 60.0% |
| 4/5 | 1.80 | -125 | 55.6% |
| Evs (1/1) | 2.00 | +100 | 50.0% |
| 6/4 | 2.50 | +150 | 40.0% |
| 2/1 | 3.00 | +200 | 33.3% |
| 3/1 | 4.00 | +300 | 25.0% |
| 5/1 | 6.00 | +500 | 16.7% |
| 10/1 | 11.00 | +1000 | 9.1% |
| 25/1 | 26.00 | +2500 | 3.8% |
| 50/1 | 51.00 | +5000 | 1.9% |
| 100/1 | 101.00 | +10000 | 1.0% |
Reading a Best Odds Comparison
When comparing odds across operators, the easiest method is to convert all prices to decimal and sort numerically — the higher decimal number is always the better price for the punter. A difference of 0.10 in decimal odds on a £50 bet translates to a £5 difference in potential return, which is material over a season of regular wagering.
Best Odds Guaranteed (BOG) is available from most major UK sportsbooks on UK and Irish horse racing — if the starting price is higher than your taken price, the operator pays out at the starting price. This is a significant benefit for punters who place ante-post bets on racing and is one of the factors that our bench awards points for in the Payout Speed axis.
Each-Way Betting Mechanics
An each-way bet is two bets in one: a win bet and a place bet, each at the stated stake. The place payout is a fraction of the win odds (typically 1/4 or 1/5 for horse racing, depending on the number of runners) on the stated number of places. On a five-place each-way horse at 12/1 (decimal 13.00) at 1/4 odds, the place return on a £10 each-way bet (£20 total) would be: 10 × ((12/4) + 1) = £40 if placed, plus £130 return if the horse wins outright.
Each-way terms vary by sport, race type and field size. Always confirm the each-way terms before placing.
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