Betting 101 · Red Meat & Cigar Club editorial
American, Decimal & Fractional Odds
Three ways to write the same price.
Example numbers — made up for illustration, not real lines
Odds are a price. The same price can be written three different ways depending on where you are: American (moneyline) odds in the United States, decimal odds across most of Europe, Canada, and Australia, and fractional odds, the traditional format of British and Irish bookmakers, especially in horse racing. Knowing all three helps when you read international coverage or compare prices.
American odds
American odds are anchored to $100. A minus number is how much you risk to win $100 (-200: risk $200 to win $100). A plus number is how much you win on $100 (+150: risk $100 to win $150). An even-money bet is written +100.
Decimal odds
Decimal odds show the total return per $1 staked, stake included. At 2.50, a $10 bet returns $25 — $15 profit plus your $10 back. At 1.50, $10 returns $15. Even money is 2.00. Decimal odds are the easiest format for math: multiply stake by the number and you have your total return. That's also why parlays are easiest to calculate in decimal.
Fractional odds
Fractional odds show profit relative to stake. At 3/2 ("three to two"), you win $3 for every $2 staked. At 1/2 ("two to one on"), you win $1 for every $2. Even money is 1/1, or "evens." Fractional odds are traditional in British racing, which is why you'll hear phrases like "100 to 1 long shot."
The same prices three ways
| American | Decimal | Fractional | $10 returns |
|---|---|---|---|
| -200 | 1.50 | 1/2 | $15.00 |
| -110 | 1.91 | 10/11 | $19.09 |
| +100 | 2.00 | 1/1 | $20.00 |
| +150 | 2.50 | 3/2 | $25.00 |
| +300 | 4.00 | 3/1 | $40.00 |
Converting between formats
- Plus American → decimal: (odds ÷ 100) + 1. Example: +150 → 1.5 + 1 = 2.50.
- Minus American → decimal: (100 ÷ |odds|) + 1. Example: -200 → 0.5 + 1 = 1.50.
- Decimal → American: if 2.00 or higher, (decimal − 1) × 100 as a plus number; if under 2.00, −100 ÷ (decimal − 1). Example: 1.50 → −100 ÷ 0.5 = -200.
- Decimal → fractional: subtract 1 and write it as a fraction. Example: 2.50 − 1 = 1.5 = 3/2.
- Fractional → decimal: divide and add 1. Example: 3/1 → 3 + 1 = 4.00.
Most U.S. sportsbook apps let you switch display formats in settings, so you rarely need to convert by hand. Knowing how helps you sanity-check what you see.
Which format is "best"?
None — they're the same price. Decimal is easiest for calculating returns and comparing long shots; American is what you'll see on U.S. broadcasts and apps; fractional is mostly tradition. What matters is understanding what the number means: the potential return and the implied probability behind it.
A note on rounding
Conversions often produce awkward decimals. -110 is technically 1.909 in decimal; books typically show 1.91. Small rounding differences add up only over very large numbers of bets, but they're a reminder that the posted price includes the book's margin. See the vig.
Worked example
Example: you see a hockey underdog listed at +165 on a U.S. app, 2.65 on a Canadian site, and 33/20 in a British newspaper. All three say the same thing. A $20 stake returns $53 total ($33 profit) in every format: 20 × 2.65 = 53. The implied probability is 100 ÷ 265 ≈ 37.7%. Once you can move between formats, international coverage of soccer, tennis, and golf becomes much easier to follow.
Common mistakes
- Reading decimal odds as profit rather than total return. A 2.00 price doubles your money; it doesn't triple it.
- Forgetting that a minus number means you risk more than you win.
- Comparing a price in one format against another without converting first.