How to Read Betting Odds
Decimal, fractional, American — odds come in different formats but they all mean the same thing. Here's how to understand them all.
What Do Odds Actually Tell You?
Betting odds serve two purposes: they show you how much you could win, and they reflect the probability (according to the bookmaker) of an outcome happening.
Lower odds = more likely to happen (smaller payout)
Higher odds = less likely to happen (bigger payout)
Manchester City at home against a struggling team might be 1.30 to win (very likely). That same team winning away at Liverpool might be 4.50 (less likely, but bigger reward if it happens).
Decimal Odds (European)
The simplest format. The number shows your total return for every £1/€1/$1 you stake, including your original stake.
How to Calculate Your Return
Total Return = Stake × Odds
Why We Use Decimal Odds
Decimal odds are the clearest format for comparing value. They're used throughout Europe and are the standard on this site. Easy math, no confusion.
Fractional Odds (UK Traditional)
Popular in the UK and Ireland. The fraction shows your profit relative to your stake. 5/1 means you win £5 for every £1 staked.
Reading Fractional Odds
When the first number is smaller than the second (like 1/2 or 4/7), the outcome is considered more likely than not. These are called "odds on."
American Odds (Moneyline)
Used primarily in the United States. These show either how much you need to stake to win $100, or how much you win from a $100 stake.
Negative (-) = Favorite
Shows how much you need to stake to win $100.
Positive (+) = Underdog
Shows how much you win from a $100 stake.
Quick Conversion Reference
| Decimal | Fractional | American | Implied Probability |
|---|---|---|---|
| 1.50 | 1/2 | -200 | 66.7% |
| 2.00 | 1/1 (evens) | +100 | 50.0% |
| 2.50 | 6/4 | +150 | 40.0% |
| 3.00 | 2/1 | +200 | 33.3% |
| 4.00 | 3/1 | +300 | 25.0% |
| 5.00 | 4/1 | +400 | 20.0% |
| 10.00 | 9/1 | +900 | 10.0% |
Understanding Implied Probability
Every odds price implies a probability — what the bookmaker believes is the chance of that outcome occurring. This is crucial for finding value.
The Formula
Implied Probability = 1 ÷ Decimal Odds × 100
Odds of 2.00 → 1 ÷ 2.00 = 0.50 = 50%
Odds of 1.50 → 1 ÷ 1.50 = 0.667 = 66.7%
Odds of 4.00 → 1 ÷ 4.00 = 0.25 = 25%
The Bookmaker's Edge
Add up the implied probabilities for all outcomes in a market (e.g., home/draw/away) and you'll get more than 100%. That extra percentage is the bookmaker's margin — their built-in profit. A typical football match might have a combined probability of 105-108%.
The Key Insight
Understanding odds isn't just about calculating payouts — it's about comparing the bookmaker's implied probability with your own assessment.
If a bookmaker prices something at 3.00 (33.3% implied probability), but you believe the true probability is 40%, that's a value bet. Over time, consistently finding these edges is what separates successful analysis from gambling.