What Are Betting Odds?
Understanding the numbers behind sports betting
If you're new to sports betting, understanding odds is the first thing you need to get right. Odds tell you two things:
- How likely an event is to happen.
- How much you can win if your bet hits.
There are three main types of odds used in sports betting:
- Decimal Odds (common in Europe, Canada, Australia)
- Fractional Odds (common in the UK)
- Moneyline Odds (common in the US)
Let's break each one down with simple examples.
1. Decimal Odds
Decimal odds are straightforward. The number shows how much you'll get back for every $1 you bet, including your stake.
Example: 1.80 or 2.50
If the odds are 2.50:
- You bet $10.
- If you win, you get $25 total (that's your $10 stake + $15 profit).
Formula:
Total Return = Stake × Odds
So, for 1.80 odds and a $20 bet:
$20 × 1.80 = $36 total return ($16 profit)
| Odds | Probability (%) | Bet Amount | Total Payout | Profit |
|---|---|---|---|---|
| 1.50 | 66.7% | $10 | $15 | $5 |
| 2.00 | 50% | $10 | $20 | $10 |
| 3.00 | 33.3% | $10 | $30 | $20 |
| 5.00 | 20% | $10 | $50 | $40 |
How to Convert Decimal Odds to Implied Probability:
Use this formula:
Implied Probability = (1 / Decimal Odds) × 100
For 2.50 odds:
(1 / 2.50) × 100 = 40% probability
This means the bookmaker believes there is a 40% chance of this outcome happening.
2. Fractional Odds
These odds show your profit relative to your stake.
Example: 5/2 or 10/1
If the odds are 5/2 (read "five to two"):
- For every $2 you bet, you win $5.
- A $10 bet would get you $25 total: $10 stake + $15 profit.
If the odds are 10/1 ("ten to one"):
- For every $1 you bet, you win $10.
- $10 bet = $100 win + $10 stake = $110 total return.
It's a bit less intuitive than decimal odds, but the profit is always shown first.
| Fractional Odds | Bet Amount | Total Payout | Profit |
|---|---|---|---|
| 1/2 | $10 | $15 | $5 |
| 1/1 (Evens) | $10 | $20 | $10 |
| 5/2 | $10 | $35 | $25 |
| 10/1 | $10 | $110 | $100 |
How to Convert Fractional Odds to Implied Probability:
Use this formula:
Implied Probability = (Denominator / (Numerator + Denominator)) × 100
For 3/1 odds:
(1 / (3+1)) × 100 = 25% probability
That means the bookmaker believes there is a 25% chance of this outcome happening.
3. Moneyline Odds
These are used mostly in the US and look confusing at first, but here's the trick:
- Negative odds (-150) show how much you need to bet to win $100.
- Positive odds (+200) show how much you'll win if you bet $100.
If the odds are -150:
- You need to bet $150 to win $100 profit.
- Total return = $250 ($150 stake + $100 profit)
If the odds are +200:
- You bet $100 to win $200 profit.
- Total return = $300
| Moneyline Odds | Bet Amount | Profit | Total Payout |
|---|---|---|---|
| -200 | $200 | $100 | $300 |
| -150 | $150 | $100 | $250 |
| +100 | $100 | $100 | $200 |
| +200 | $100 | $200 | $300 |
| +500 | $100 | $500 | $600 |
How to Convert Moneyline Odds to Implied Probability:
For negative odds (-150):
Implied Probability = (-Odds) / ((-Odds) + 100) × 100
= (150 / (150+100)) × 100 = 60% probability
For positive odds (+200):
Implied Probability = 100 / (Odds + 100) × 100
= (100 / (200+100)) × 100 = 33.3% probability
Comparing the Odds Formats
All three odds formats represent the same thing but in different ways. Here's how the same bet looks in each format:
| Outcome | Decimal | Fractional | Moneyline | $10 Bet Wins |
|---|---|---|---|---|
| Favorite | 1.50 | 1/2 | -200 | $5 profit |
| Even Odds | 2.00 | 1/1 | +100 | $10 profit |
| Underdog | 3.00 | 2/1 | +200 | $20 profit |
| Big Underdog | 6.00 | 5/1 | +500 | $50 profit |
Why Odds Change
Odds shift based on:
- Team news (injuries, lineups)
- Betting volume
- Market movement
If a lot of people are betting on one outcome, the bookmaker might adjust the odds to balance the risk.
Final Tips for Understanding Odds
- Low odds = higher chance to win, lower payout.
- High odds = lower chance to win, higher payout.
- Different sportsbooks may offer slightly different odds.
- Always compare odds to find the best value for your bets.
- Convert odds into probability to understand the bookmaker's view.
Odds aren't just about payouts—they reflect implied probability. You can reverse-engineer this:
- Decimal odds → Implied probability = 1 / odds
- Example: 2.00 odds = 1 / 2 = 0.50 → 50% chance
Always consider whether the odds represent value, not just potential winnings. That's where smart betting begins.
Conclusion
Understanding betting odds is crucial for making smart bets. Whether you're betting on the Premier League, Champions League, or any other match, knowing how odds work helps you assess risk, find value, and make better decisions.
If you're serious about betting, learn to read all three odds formats—even if you prefer one. This knowledge will give you an edge when comparing bets across different sportsbooks.
Stick with the format that makes the most sense to you, understand what the numbers mean, and always bet responsibly.