Odds Converter — Decimal, Fractional & American

Convert Your Odds

How to Convert Between Odds Formats

Decimal to Fractional

Subtract 1 from the decimal odds, then convert to the simplest fraction. For example, 2.50 - 1 = 1.50 = 3/2. Decimal 3.25 = 2.25 = 9/4.

Decimal to American

If decimal >= 2.00: American = (decimal - 1) x 100, with a + sign. If decimal < 2.00: American = -100 / (decimal - 1). For example, 2.50 = +150; 1.50 = -200.

Fractional to Decimal

Divide the numerator by the denominator and add 1. For example, 5/2 = 5/2 + 1 = 3.50. 3/1 = 3/1 + 1 = 4.00.

American to Decimal

If positive (+): decimal = (american / 100) + 1. If negative (-): decimal = (-100 / american) + 1. For example, +150 = 2.50; -200 = 1.50.

Implied Probability

The implied probability is 1 / decimal_odds x 100. For decimal 2.50, the implied probability is 1/2.50 = 40%. This represents the bookmaker's assessment of the likelihood of that outcome.

Common Odds Conversions

Which Odds Format Should You Use?

The odds format you use depends largely on your location and the bookmaker:

• Decimal odds are the standard in Europe, Australia, Canada, and most of the world. They are the easiest to calculate returns for: simply multiply your stake by the decimal odds.
• Fractional odds are traditional in the UK and Ireland. They show the profit relative to the stake. For example, 5/2 means you profit 5 units for every 2 staked.
• American odds (moneyline) are standard in the US. Positive numbers show profit on a 100-unit stake; negative numbers show how much you need to stake to win 100 units.

For dutching calculations, decimal odds are always the easiest to work with because the math is straightforward. Use this converter to translate odds from any format into decimal before using our dutching calculator.

Odds Conversion Table — Common Values

Use this quick-reference table to find common odds conversions at a glance. Each row shows the same probability expressed in all four formats.

Fractional odds are simplified to their lowest terms. Some bookmakers display slightly different fractions for the same decimal value depending on rounding conventions.

How to Use the Odds Converter

Using the odds converter above is straightforward. Follow these steps:

1. Choose your input format — type the odds you have into the corresponding field: Decimal (e.g. 2.50), Fractional (e.g. 3/2), or American (e.g. +150).
2. Watch the conversion happen instantly — the other two fields update automatically as you type. No button clicking required.
3. Read the implied probability — the field below the inputs shows the bookmaker's implied probability, which tells you the percentage chance the odds represent.
4. Use the result in your dutching calculations — once you have the odds in decimal format (the easiest format to work with), enter them into our dutching calculator to plan your bets.
5. Reference the conversion table — if you are working with common odds values, check the table below for a quick lookup without typing anything.

The converter works for any odds value from 1.01 upwards. Decimal odds below 1.01 are not valid in standard betting markets.

Worked Examples: Converting Between All Three Formats

Example 1: Football Match — Decimal 2.10

You see a team priced at 2.10 in decimal format on a European bookmaker. You want to know what this looks like in fractional and American formats.

• Decimal to Fractional: 2.10 - 1 = 1.10 = 11/10
• Decimal to American: Since 2.10 > 2.00, American = (2.10 - 1) × 100 = +110
• Implied Probability: 1 ÷ 2.10 = 47.6%

So decimal 2.10 equals 11/10 in fractional and +110 in American. A 50 EUR stake returns 105 EUR (50 × 2.10), giving you 55 EUR profit.

Example 2: Horse Racing — Fractional 7/2

A UK bookmaker offers a horse at 7/2 fractional odds. You need it in decimal for your dutching spreadsheet.

• Fractional to Decimal: 7 ÷ 2 + 1 = 3.50 + 1 = 4.50
• Fractional to American: Since 4.50 > 2.00, American = (4.50 - 1) × 100 = +350
• Implied Probability: 1 ÷ 4.50 = 22.2%

So 7/2 equals decimal 4.50 and American +350. A 20 EUR stake returns 90 EUR (20 × 4.50), with 70 EUR profit.

Example 3: US Sports — American -200

An American moneyline shows -200. You need the decimal equivalent for international comparison.

• American to Decimal: Since -200 is negative, Decimal = (-100 ÷ -200) + 1 = 0.50 + 1 = 1.50
• American to Fractional: 1.50 - 1 = 0.50 = 1/2
• Implied Probability: 1 ÷ 1.50 = 66.7%

So -200 American equals decimal 1.50 and fractional 1/2. A 100 EUR stake returns 150 EUR (100 × 1.50), with 50 EUR profit. Note that negative American odds always represent favourites — you need to stake 200 to win 100.

Example 4: Tennis — American +400

An underdog in a tennis match is listed at +400 American odds. Let us convert this.

• American to Decimal: Since +400 is positive, Decimal = (400 ÷ 100) + 1 = 4.00 + 1 = 5.00
• American to Fractional: 5.00 - 1 = 4.00 = 4/1
• Implied Probability: 1 ÷ 5.00 = 20.0%

So +400 American equals decimal 5.00 and fractional 4/1. Positive American odds always represent underdogs — a 100 EUR stake returns 500 EUR, with 400 EUR profit.

Frequently Asked Questions About Odds Conversion

Why do bookmakers use different odds formats?

Different odds formats evolved in different regions. Fractional odds originated in the UK with horse racing tradition. Decimal odds became the standard across Europe and Australia because they are simpler to calculate with. American odds developed separately in the United States. Each format represents the same underlying probability — the choice is purely about convention and familiarity.

Which odds format is best for dutching?

Decimal odds are by far the easiest to use for dutching calculations. Dutching involves dividing stakes proportionally to the inverse of the odds, and decimal odds make this arithmetic straightforward. Fractional odds require an extra conversion step, while American odds are especially cumbersome for dutching because positive and negative values follow different rules. Always convert to decimal before using our dutching calculator.

What is implied probability and why does it matter?

Implied probability is the percentage chance that the odds represent. For decimal odds of 3.00, the implied probability is 1/3 = 33.3%. If you believe the actual chance of the outcome is higher than 33.3%, the bet offers value. Implied probability also helps you understand the bookmaker's margin — the sum of implied probabilities across all outcomes in a market always exceeds 100%, with the excess being the bookmaker's overround.

How do I convert odds manually without a calculator?

The core formulas are simple once you memorise them. For decimal to fractional: subtract 1 and simplify. For decimal to American: if decimal ≥ 2.00, multiply (decimal - 1) by 100 and add a + sign; if decimal < 2.00, divide -100 by (decimal - 1). For fractional to decimal: divide numerator by denominator and add 1. For American to decimal: if positive, divide by 100 and add 1; if negative, divide -100 by the American value and add 1. With practice, the most common conversions become second nature.

Can I convert odds from a screenshot or printed materials?

Yes — simply read the odds in whatever format is presented and type them into the corresponding field of our converter. The tool handles the conversion instantly. For fractional odds printed in small text (common on race cards), double-check the format is correct (e.g. 5/2, not 5-2 or 5:2) before entering it.