Free calculator
Odds converter
Type a price in any format. The rest update as you go, along with the probability the price implies.
e.g. +150 or -200
includes your stake
profit relative to stake
percent, before removing the vig
Implied probability includes the sportsbook's margin. Two sides of a market will normally add up to more than 100 percent.
Comparing prices across books?
Converting by hand is fine for one price. BetSuite watches your sportsbooks and flags the moments they disagree enough to matter.
Download Free →The three formats, and why they exist
American odds are built around $100. A positive number is the profit on a $100 stake, so +150 wins $150. A negative number is what you must stake to win $100, so -200 means risking $200 for a $100 profit. It is the default across US sportsbooks.
Decimal odds are the cleanest to work with: multiply your stake by the number and you have your total return, stake included. 2.50 turns $100 into $250. This is standard in Europe, Canada and on exchanges, and it is what most arbitrage math runs on.
Fractional odds show profit against stake. 3/2 means three in profit for every two staked. Common in the UK and in horse racing, rarer elsewhere.
Odds conversion chart, and what each price returns
The same price in all four notations, with what a $100 bet brings back in total if it wins. Stake is included in that last column, so a $100 bet at +150 returns $250: your $100 back plus $150 in profit.
| American | Decimal | Fractional | Implied | $100 returns |
|---|---|---|---|---|
| -400 | 1.25 | 1/4 | 80.00% | $125.00 |
| -300 | 1.33 | 1/3 | 75.00% | $133.33 |
| -250 | 1.40 | 2/5 | 71.43% | $140.00 |
| -200 | 1.50 | 1/2 | 66.67% | $150.00 |
| -150 | 1.67 | 2/3 | 60.00% | $166.67 |
| -120 | 1.83 | 5/6 | 54.55% | $183.33 |
| -110 | 1.91 | 10/11 | 52.38% | $190.91 |
| +100 | 2.00 | 1/1 | 50.00% | $200.00 |
| +110 | 2.10 | 11/10 | 47.62% | $210.00 |
| +120 | 2.20 | 6/5 | 45.45% | $220.00 |
| +150 | 2.50 | 3/2 | 40.00% | $250.00 |
| +200 | 3.00 | 2/1 | 33.33% | $300.00 |
| +250 | 3.50 | 5/2 | 28.57% | $350.00 |
| +300 | 4.00 | 3/1 | 25.00% | $400.00 |
| +400 | 5.00 | 4/1 | 20.00% | $500.00 |
| +500 | 6.00 | 5/1 | 16.67% | $600.00 |
The formulas, if you would rather do it by hand
American odds split into two rules depending on the sign, which is the part that trips people up. A positive number is the profit on a $100 bet. A negative number is what you have to stake to profit $100.
Positive American to decimal: divide by 100, add 1. +250 becomes 250/100 + 1 = 3.50.
Negative American to decimal: divide 100 by the number, add 1. -200 becomes 100/200 + 1 = 1.50.
Decimal to implied probability: divide 1 by the decimal. 2.50 gives 1/2.50 = 40 percent.
Fractional to decimal: divide the fraction out and add 1. 3/2 becomes 1.5 + 1 = 2.50.
Turning a price into a payout
Once a price is in decimal, the payout is one multiplication. Multiply your stake by the decimal for the total return, or by the decimal minus 1 for the profit alone.
A $40 bet at -120 converts to 1.83, so it returns 40 x 1.83 = $73.33 in total, of which $33.33 is profit. A $25 bet at +300 converts to 4.00 and returns $100, with $75 of that being profit. This is the whole of it: the format is only ever presentation, and the decimal is the number that does the work.
The converter above handles the format half. For stake sizing rather than payout, the Kelly calculator works out what fraction of a bankroll a price justifies, and the expected value calculator shows whether the price is worth taking at all.
Why implied probability is the number that matters
Format is presentation. Implied probability is the price. Once you convert every book to a probability, comparing them becomes trivial, and you can see the sportsbook's margin sitting on top.
Take a standard -110 on both sides of a market. Each implies 52.38 percent, and together they total 104.76 percent. That extra 4.76 percent is the vig. When two different books disagree enough that the total drops below 100 percent, both sides can be backed for the same return either way, which is what the arbitrage calculator works out. Our sportsbook comparisons cover where those gaps tend to open up.
Common questions
How do you convert American odds to decimal?
For a positive American price, divide by 100 and add 1: +150 becomes 2.50. For a negative price, divide 100 by the absolute value and add 1: -200 becomes 1.50. Decimal odds include your stake, so a $10 bet at 2.50 returns $25 in total rather than $25 in profit.
What is implied probability?
Implied probability is the chance a price represents, found by dividing 1 by the decimal odds. Odds of 2.50 imply 40 percent. It is the number worth comparing between sportsbooks, because it strips the format away and shows what each book actually thinks.
Why do implied probabilities add up to more than 100 percent?
The excess is the sportsbook's margin, known as the vig or juice. On a two-way market priced at -110 on both sides, the implied probabilities total about 104.8 percent, so roughly 4.8 percent is the book's built-in edge. When two books disagree enough that the total falls below 100 percent, that is an arbitrage.
Are fractional odds the same as decimal odds?
They describe the same price differently. Fractional odds show profit relative to stake, so 6/4 means four staked returns six in profit. Decimal odds show the total return including stake, so 6/4 is 2.50. Fractional is common in the UK and in horse racing; decimal is standard across Europe and on betting exchanges.
How do I work out a payout from odds?
Convert the price to decimal, then multiply by your stake for the total return. A $40 bet at -120 is 40 x 1.83 = $73.33 back, $33.33 of it profit. Multiply by the decimal minus 1 if you want the profit on its own.
What does a minus sign on American odds mean?
It marks the favorite, and it tells you the stake needed to profit $100. At -200 you risk $200 to win $100. A plus sign marks the underdog and tells you the profit on a $100 stake, so +200 wins $200 from $100.