Odds Calculator

What this odds calculator does

Enter odds in any one format and the calculator fills in the other three. American odds are what US sportsbooks post. Decimal odds are what European books use. Fractional odds show the profit ratio. Implied probability is what the odds say about the chance of winning.

Type a stake and you also get the profit and total payout for that bet. Change any field and everything recalculates instantly.

How the math works

American odds of +150 mean a $100 bet pays $150 profit, so the decimal is 2.50 and the implied probability is 40 percent. American odds of -200 mean you must risk $200 to win $100, so the decimal is 1.50 and the implied probability is 66.67 percent.

Decimal odds are the total return per unit staked, so 2.50 means a $100 bet returns $250 total ($150 profit). Fractional odds of 3/2 mean the same thing: profit of 3 for every 2 staked, which is decimal 2.50.

Worked example

You see a bet at -110. The decimal is 1.909, the implied probability is 52.38 percent, and a $110 stake returns $100 profit and $210 total. Now compare that to a bet at +130: decimal 2.30, implied 43.48 percent, and a $110 stake returns $143 profit and $253 total.

The no-vig calculator below removes the bookmaker margin. Enter both sides of a market in American odds and it shows the vig, each side's no-vig probability, and the fair American odds.

Common mistakes

Do not confuse implied probability with the real chance of winning. Implied probability includes the bookmaker margin, so it always sums above 100 percent for a two-way market. The real chance is lower.

A common error is adding instead of multiplying when converting decimal odds to a parlay. Two legs at 2.0 and 1.5 combine to 3.0, not 2.5. Use the parlay calculator for that.

Frequently asked questions