Calculation results
| Decimal Odds | |
|---|---|
| Fractional Odds | |
| American Odds | |
| Implied Probability | |
| Potential Payout |
Odds Calculator
What Is the Odds Calculator?
The odds calculator converts between the four main odds formats used in betting and probability: American, decimal, fractional, and implied. Enter odds in any format and an optional bet amount, and the tool displays the equivalent odds in every other format plus the implied probability and your potential payout and winnings.
Formats exist because traditions differ. American moneylines dominate US sportsbooks, decimal odds rule Europe and Australia, fractional odds remain standard in UK horse racing, and implied probability is the raw language of chances underneath them all. Moving between them fluently is the first skill of any sharp bettor.
Odds Formats at a Glance
Reading each format is straightforward once shown:
American odds use plus and minus signs. Minus 150 means you stake 150 to win 100, so the favorite is on the minus side. Plus 200 means a 100 stake wins 200, marking the underdog.
Decimal odds multiply your stake, so a 2.50 line on a 10 bet returns 25 total, which is 15 in winnings and your 10 back. Fractional odds express winnings as a ratio, so 5 to 1 pays 5 for every 1 staked.
Implied probability is what the odds secretly claim. Decimal odds of 2.50 imply a 40 percent chance, while minus 150 implies 60 percent. The two implied probabilities never sum to 100 percent across a two way market, and that gap is the bookmaker’s margin.
How to Convert Between Odds Formats
The arithmetic is mechanical. For positive American odds o, decimal equals o divided by 100 plus 1, so 150 becomes 2.50. For negative American odds, decimal equals 100 divided by the absolute value plus 1, so minus 150 becomes about 1.667. Fractional counts winnings over stake, thus positive American odds equal the fraction directly, 150 over 100, reduced to 3 to 2.
Implied probability for positive American odds is 100 divided by odds plus 100, and for negative odds it is the absolute value divided by its absolute plus 100. A decimal o corresponds to 1 divided by o. The calculator runs all of these simultaneously, so one entry gives every equivalent.
Using Implied Probability to Find Value
Comparing implied probability with your own estimate of the true chance is the entire basis of value betting. If you believe an outcome has a 50 percent chance but the odds imply only 40 percent, the price is in your favor; if the market implies 70 percent and you see 55, the bet is overpriced.
The payout function also helps in offices and communities: fund splits, prize pools, and parlay math all reduce to the same conversions. Enter your stake once and read potential winnings across formats, including how a parlay’s decimal multipliers compound when you multiply them together.
Frequently Asked Questions
How do I convert American odds to decimal?
For positive odds, divide by 100 and add 1, so 150 becomes 2.50. For negative odds, divide 100 by the absolute value and add 1, so minus 150 becomes about 1.67.
What is implied probability?
It is the chance of an outcome that the odds encode, before the bookmaker’s margin. Decimal odds of 2.50 imply 40 percent, and American odds of minus 150 imply 60 percent.
Do minus odds mean favorite?
Yes. In American format, the minus sign marks the favorite that requires a larger stake to win 100, while plus odds mark the underdog paying more than even money.
How is my payout calculated?
Multiply your stake by the decimal odds to get the total return, which includes your original stake back. Winnings alone are that total minus your stake.
Why do the two sides of a game add up to more than 100 percent?
Because the bookmaker builds in a margin. The extra implied probability above 100 percent is the house edge, typically a few percent depending on the market.