Odds Converter
Type any odds in any format. The other two formats and the implied probability update automatically. Use this to compare lines across books that show odds differently.
Result
How odds formats compare
US sportsbooks default to American odds, where favorites carry minus signs (e.g. -150) and underdogs carry plus signs (e.g. +130). European books use decimal odds, which already include the original stake (e.g. 2.50 means a $1 winning bet returns $2.50 total). Fractional odds, common in UK racing, list the profit relative to stake (e.g. 3/2 means win $3 for every $2 staked).
Conversion formulas
- American positive (+X) to decimal:
(X / 100) + 1 - American negative (-X) to decimal:
(100 / X) + 1 - Decimal (D) to American: if D ≥ 2 use
(D - 1) × 100, else use-100 / (D - 1) - Implied probability from decimal:
1 / D × 100%
Why this matters
Tennessee sportsbooks default to American odds, but bet365 and some international markets show decimal. When line shopping across multiple books, converting to a common format prevents costly misreads. Implied probability is the cleanest way to compare two lines: lower implied probability at the same outcome means better value.
Frequently Asked Questions
What's the difference between American, decimal, and fractional odds?
American odds use positive numbers for underdogs (+150 means $150 profit on $100 stake) and negative for favorites (-150 means $150 stake to win $100). Decimal odds (2.50) include stake in the return. Fractional odds (3/2) show profit relative to stake. The three formats describe identical probability.
Which odds format do TN sportsbooks use by default?
All ten Tennessee sportsbooks default to American odds. Bet365 lets you switch the display to decimal in settings, which can help if you also bet international soccer markets.
How accurate is this odds converter?
The converter rounds to three decimal places on decimal odds and to the nearest integer on American odds. Implied probability is shown to two decimal places. Sportsbooks may round slightly differently, so a converted American value can occasionally differ by one unit from a book's quote.
Can I convert player prop odds?
Yes. The converter works for any odds format on any market type: moneyline, spread, total, player props, futures, parlays. Just enter the offered odds in any format and read the equivalent in the others.
Why do fractional odds show whole numbers like 3/2?
Fractional odds approximate decimal odds with the nearest clean fraction. 3/2 means win $3 profit for every $2 staked, which is decimal 2.50 and American +150. The calculator finds the closest clean fraction to the input.