For bettors

Odds converter

The same price shown four ways. Edit any field — decimal, fractional, American or implied probability — and the rest update.

Enter a price

Decimal

Fractional

American

Implied probability, %

Your bet

Stake

Profit if it wins—

Total return—

Break-even win rate—

Common conversions

Dec	Frac	Am	%

Implied probability from a single price includes the bookmaker margin — it is the break-even win rate for the bet, not a true probability. Fractional odds are shown as the nearest clean fraction.

The four ways to write the same price

Decimal, fractional, American and implied probability are all the same number in different clothes. Decimal (2.50) is the total return per unit staked, used across Europe and by exchanges. Fractional (3/2) is profit-to-stake, traditional in the UK and Ireland. American (+150 / −200) shows the profit on a 100 stake for underdogs and the stake needed to win 100 for favourites. Implied probability (40%) is 1 ÷ decimal odds — the win rate at which the price breaks even.

Reading the margin

Implied probability is not the bookmaker's honest opinion of the chance — it is that opinion with a margin added. Convert both sides of a two-way market and add the implied probabilities: the total comes to something like 104–107%. That 4–7% overround is the book's edge. On a three-way market or an accumulator it is larger. Comparing the overround across bookmakers is the quickest way to see who prices a market tightest.

From price to payout

Total return is always stake × decimal odds; profit is stake × (decimal − 1). The converter fills this in for whatever stake you enter, so you can read a fractional or American price and immediately see the money without doing the format conversion in your head.

Frequently asked questions

What does +150 mean?

American odds. +150 returns $150 profit on a $100 stake plus your stake back — total $250. That is 2.50 in decimal and a 40% break-even win rate.

How do I convert decimal odds to a payout?

Total return = stake × decimal odds. Profit = stake × (decimal − 1). At 2.50 a $100 bet returns $250 and profits $150.

Is implied probability the bookmaker's real estimate?

No. It is the break-even win rate for that price. Add the implied probabilities of all outcomes and they exceed 100% — the excess is the margin.

What does −200 mean and how is it different from +200?

−200 is a favourite: you stake 200 to win 100 profit (decimal 1.50). +200 is an underdog: you stake 100 to win 200 profit (decimal 3.00). Negative American odds are for prices below 2.00, positive for prices above.

How do I turn a fraction like 5/2 into decimal?

Divide the numerator by the denominator and add 1: 5 ÷ 2 + 1 = 3.50. Going back, subtract 1 and express as a fraction: 3.50 − 1 = 2.50 = 5/2.

Why do the implied probabilities of a match add up to more than 100%?

Because each price has the bookmaker's margin baked in. The excess over 100% is the overround. To get fair, no-vig probabilities, divide each implied probability by the total — or use the bookmaker margin / vig remover.

Do exchanges and bookmakers use the same odds?

Both quote decimal odds, but an exchange price is set by other bettors and is usually tighter, with commission taken from winnings instead of built into the price. A bookmaker price includes the margin up front. Convert both to implied probability to compare them fairly.

Does the converter round, and can that cost me money?

It displays a rounded value but calculates on the full precision. Bookmakers themselves round fractional and American prices to standard steps, which is a small source of value difference between formats — always bet at the price actually shown on the slip.

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