How do you read betting odds?

Three notations, one idea

Every odds format is answering the same question: if this bet wins, how much do you get back relative to what you staked? The three common notations just express that ratio differently.

Fractional odds (5/1, 4/5)

The traditional British format. The first number is the profit, the second is the stake. At 5/1, a $10 bet that wins returns $50 profit plus your $10 stake back — $60 total. At 4/5 ("odds-on"), you must stake $5 to win $4 of profit, so a winning $10 bet returns $18 total. Fractional odds smaller than 1/1 mean the outcome is priced as more likely than not.

Decimal odds (6.00, 1.80)

The standard in continental Europe and on most betting exchanges, and the easiest to compute with. The number is the total return per unit staked, stake included. A winning $10 bet at 6.00 returns $60; at 1.80 it returns $18. Converting is trivial: decimal odds equal the fractional odds plus one. 5/1 becomes 6.00; 4/5 becomes 1.80.

Moneyline odds (+500, -125)

The American format, built around a $100 reference stake. A positive number is the profit on a $100 stake: +500 means a $100 bet wins $500. A negative number is the stake required to win $100: -125 means you must risk $125 to win $100 of profit. Even money is written +100. Moneylines express exactly the same ratios as the other formats — +500 is 5/1 is 6.00.

Implied probability

Any price can be turned into a probability: divide 1 by the decimal odds. A price of 2.00 implies 50 percent; 6.00 implies about 16.7 percent; 1.25 implies 80 percent. This is what the price treats as the likelihood of the outcome.

Two cautions. First, the implied probability is not the true probability — nobody knows the true probability of a football game. Second, a bookmaker's prices across all outcomes of an event sum to more than 100 percent, because a margin is built into them. That margin is the subject of our page on why the odds add up to more than 100 percent.

A worked example

Suppose a team is listed at -200. Converting: risk $200 to win $100, so the decimal odds are 1.50 and the fractional odds are 1/2. Implied probability is 1 ÷ 1.50 ≈ 66.7 percent. A winning $10 bet returns $15 total — $5 of profit. Our odds format reference table has these conversions laid out for the most common prices.

Where the numbers come from

Odds are set by operators and move with the money wagered; they are prices, not predictions handed down from anywhere neutral. In regulated markets, what is overseen is the operator's conduct — licensing, fairness of settlement, handling of customer funds. The UK Gambling Commission's public pages are a good example of what consumer-facing regulation looks like, and the Responsible Gambling Council publishes plain-language education on how gambling products actually work. Understanding the notation is step one; understanding that every price includes a margin against you is step two.