How Odds Work: Decimal vs. Fractional vs. American
If you’re new to betting, one of the first hurdles is understanding how odds work. While most sportsbooks let you toggle between decimal, fractional, and American odds, the default display can be confusing. This guide will break down each type and show you how to read them.
Decimal Odds
Where used: Europe, Asia, Australia, New Zealand
How to calculate:
Multiply your stake by the decimal number to get the total return (not just profit).
Example:
- Lakers (1.5 odds): Bet $100 → Return $150 ($50 profit)
- Spurs (2.2 odds): Bet $100 → Return $220 ($120 profit)
🔹 Decimal odds = stake + profit
🔹 Payouts are rounded to the nearest cent
Fractional Odds
Where used: UK, Ireland, horse racing worldwide
How to calculate:
The fraction tells you how much you win relative to your stake.
Example:
- Tottenham (3/2): Bet $2 → Win $3 → Return $5
- Arsenal (7/4): Bet $4 → Win $7 → Return $11
- Draw (23/10): Bet $10 → Win $23 → Return $33
🔹 Easier to calculate with bets in multiples of 10
🔹 Common in soccer and horse racing
American Odds
Where used: United States, occasionally Latin America
How to read:
- Negative odds (–) = Favorite → Bet that amount to win $100
- Positive odds (+) = Underdog → Bet $100 to win that amount
Example:
- Chiefs (-200): Bet $200 → Win $100 → Return $300
- Broncos (+170): Bet $100 → Win $170 → Return $270
🔹 Easier to understand in $10 or $100 increments
🔹 Sportsbooks usually calculate everything for you
Odds Conversion Chart
| Decimal | Fractional | American |
|---|---|---|
| 1.01 | 1/100 | -10000 |
| 1.05 | 1/20 | -2000 |
| 1.10 | 1/10 | -1000 |
| 1.20 | 1/5 | -500 |
| 1.50 | 1/2 | -200 |
| 1.91 | 10/11 | -110 |
| 2.00 | 1/1 | +100 |
| 2.20 | 6/5 | +120 |
| 2.50 | 3/2 | +150 |
| 3.00 | 2/1 | +200 |
| 4.00 | 3/1 | +300 |
| 5.00 | 4/1 | +400 |
(Full table omitted here for brevity — let me know if you want the full version formatted in Excel or table graphic.)
Quick Tip
Most odds include a 10% vigorish (a.k.a. juice) taken by the sportsbook. This shows as:
- Decimal: 1.91
- Fractional: 10/11
- American: -110
Final Thoughts
When converting odds:
- Use decimal odds as your base
- Always add 1 to profit-only odds (fractional & American) to match total returns
- Don’t stress over weird amounts — sportsbooks do the math for you
