Do you want to understand how each of the different sports betting odds formats work?
In this article I provide the formulas to calculate the potential winnings using any format of your choice. I also explain how to convert any format to/from the, preferable, decimal odds format.
Article Contents
1. Decimal Odds
Decimal odds are the default format across Europe — hence the name “European decimal odds.” They’re the easiest and most transparent odds to use, and the go-to format for most professional bettors and traders.
Importantly, decimal odds show the total return (stake included).
Profit Calculation
Formula: Stake × (Decimal – 1)
Examples
- 2.0 → £100 profit on a £100 stake.
- 5.0 → £400 profit on a £100 stake.
- 10.0 → £900 profit on a £100 stake.
Learn more about the decimal odds format.
2. Fractional Odds
In the UK and Ireland, mainstream bookmakers have always used fractional odds as the default (e.g. 6/4, 1/3, 2/1). They’re simple to use but don’t always make it easy to compare value between prices.
When used in calculations, fractional odds show the profit only (stake not included).
Profit Calculation
Formula: Stake × Fraction
Examples
- 2/1 → £200 profit on a £100 stake.
- 1/2 → £50 profit on a £100 stake.
- 1/1 → £100 profit on a £100 stake (“evens”).
To Convert to Decimal Odds
Formula: Fraction + 1
Examples
- 3/1 → 3.0 + 1 = 4.0 decimal odds.
- 1/2 → 0.5 + 1 = 1.5 decimal odds.
- 1/1 → 1 + 1 = 2.0 decimal odds.
To convert decimal odds to fractions: Decimal – 1, then simplify to the nearest whole integers (e.g. 3.75 – 1 = 2.75/1 ≈ 11/4).
Learn more about the fractional odds format.
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3. American Odds
American odds (also called “moneyline odds” or “lines”) are widely used in the US. They work differently for favourites and underdogs, but both are expressed in units of $100.
- If the odds are below evens (2.0 decimal), they’re negative (–). This shows how much you must wager to win $100.
- If the odds are above evens (2.0 decimal), they’re positive (+). This shows how much you will profit on a $100 bet.
American odds are rarely used in the UK or Europe, where fractional and decimal odds are preferred.
Profit Calculation (Favourites)
Formula: (–100 / Odds) × Stake
Examples
- –200 → (–100/–200) = 1/2. $50 profit on $100 stake.
- –400 → (–100/–400) = 1/4. $25 profit on $100 stake.
- –500 → (–100/–500) = 1/5. $10 profit on $50 stake.
Profit Calculation (Underdogs)
Formula: (Odds / 100) × Stake
Examples
- +200 → (200/100) = 2/1. $200 profit on $100 stake.
- +300 → (300/100) = 3/1. $300 profit on $100 stake.
- +500 → (500/100) = 5/1. $250 profit on $50 stake.
To Convert to Decimal Odds (Favourites)
Formula: (–100 / Odds) + 1
Examples
- –500 → (–100/–500) + 1 = 1.2 decimal odds.
- –400 → (–100/–400) + 1 = 1.25 decimal odds.
- –100 → (–100/–100) + 1 = 2.0 decimal odds.
To Convert to Decimal Odds (Underdogs)
Formula: (Odds / 100) + 1
Examples
- +500 → (500/100) + 1 = 6.0 decimal odds.
- +400 → (400/100) + 1 = 5.0 decimal odds.
- +200 → (200/100) + 1 = 3.0 decimal odds.
To convert decimal to American odds:
- If decimal ≥ 2.0 → (Decimal – 1) × 100.
- If decimal < 2.0 → (–100) / (Decimal – 1).
Learn more about the American odds format.
4. Hong Kong Odds
Hong Kong odds are popular in Asia. They work like fractional odds but are shown in decimal form. Calculations give the profit (stake not included).
Profit Calculation
Formula: Stake × Odds
Examples
- 2.0 → £200 profit on a £100 stake.
- 0.5 → £50 profit on a £100 stake.
- 3.0 → £150 profit on a £50 stake.
To Convert to Decimal Odds
Formula: Odds + 1
Examples
- 0.4 → 0.4 + 1 = 1.4 decimal odds.
- 5.0 → 5 + 1 = 6.0 decimal odds.
- 1.5 → 1.5 + 1 = 2.5 decimal odds.
To convert decimal to Hong Kong odds: Decimal – 1.
Learn more about the Hong Kong odds format.
5. Indonesian Odds
Indonesian odds resemble American odds, but are based on $1 units instead of $100. Negative values show how much you need to bet to win $1; positive values show profit on a $1 bet.
Profit Calculation (Favourites)
Formula: Stake × (–1 / Odds)
Examples
- –2.0 → $0.50 profit on a $1 stake.
- –1.25 → $0.80 profit on a $100 stake.
- –1.5 → $40 profit on a $60 stake.
Profit Calculation (Underdogs)
Formula: Stake × Odds
Examples
- +4.0 → $400 profit on a $100 stake.
- +3.0 → $300 profit on a $100 stake.
- +5.0 → $250 profit on a $50 stake.
To Convert to Decimal Odds (Favourites)
Formula: (–1 / Odds) + 1
Examples
- –5.0 → (–1/–5) + 1 = 1.2 decimal odds.
- –4.0 → (–1/–4) + 1 = 1.25 decimal odds.
- –1 → (–1/–1) + 1 = 2.0 decimal odds.
To Convert to Decimal Odds (Underdogs)
Formula: Odds + 1
Examples
- +5.0 → 5 + 1 = 6.0 decimal odds.
- +4.0 → 4 + 1 = 5.0 decimal odds.
- +2.0 → 2 + 1 = 3.0 decimal odds.
To convert decimal to Indonesian odds:
- If decimal ≥ 2.0 → Decimal – 1.
- If decimal < 2.0 → (–1) / (Decimal – 1).
Learn more about the Indonesian odds format.
6. Malaysian Odds
Malaysian odds invert the Indonesian/American system: negative (–) values represent the underdog, while positive (+) values represent the favourite.
Profit Calculation (Favourites)
Formula: Stake × Odds
Examples
- +5.0 → $500 profit on a $100 stake.
- +4.0 → $400 profit on a $100 stake.
- +1.0 → $50 profit on a $50 stake.
Profit Calculation (Underdogs)
Formula: Stake × (–1 / Odds)
Examples
- –2.0 → $0.50 profit on a $1 stake.
- –1.25 → $0.80 profit on a $100 stake.
- –1.5 → $40 profit on a $60 stake.
To Convert to Decimal Odds (Positive)
Formula: Odds + 1
Examples
- +5.0 → 6.0 decimal odds.
- +4.0 → 5.0 decimal odds.
- +1.0 → 2.0 decimal odds.
To Convert to Decimal Odds (Negative)
Formula: (–1 / Odds) + 1
Examples
- –5.0 → (–1/–5) + 1 = 1.2 decimal odds.
- –4.0 → (–1/–4) + 1 = 1.25 decimal odds.
- –0.6 → (–1/–0.6) + 1 ≈ 2.67 decimal odds.
To convert decimal to Malaysian odds:
- If decimal ≤ 2.0 → Decimal – 1.
- If decimal > 2.0 → (–1) / (Decimal – 1).
Learn more about the Malaysian odds format.
7. The Probability (Implied Odds)
Probabilities aren’t shown by bookmakers or exchanges, but they’re vital for identifying value bets. Implied probability converts odds into a percentage chance of an event happening.
Once odds are in decimal format, you can quickly convert them to an implied % chance.
To Convert From Decimal Odds
Formula: 1 / Decimal
Examples
- 5.0 → 1/5 = 0.2 = 20% chance.
- 2.0 → 1/2 = 0.5 = 50% chance.
- 1.5 → 1/1.5 ≈ 0.667 = 66.7% chance.
To Convert to Decimal Odds
Formula: 100 / Chance %
Examples
- 40% → 100/40 = 2.5 decimal odds.
- 90% → 100/90 ≈ 1.11 decimal odds.
- 25% → 100/25 = 4.0 decimal odds.
Learn more about implied probability.
Final Words of Advice
While using an online odds conversion calculator is the easiest way to find equivalent odds, understanding the formulas is crucial if you want to build your own betting strategy using Excel or similar tools.
If you can choose your odds format, I recommend decimal “European” odds for their simplicity. Unlike others, decimal odds are intuitive: the higher the number, the less likely the event, and the bigger the payout.
There’s also one more odds format you might want to learn about: spread betting odds. They work very differently from fixed odds, so I’ve published a separate guide: Spread Betting Odds Explained.
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