Type in any field. The others update in real time. Tap any result to copy it. Convert American (+140 / −120), decimal (2.40), fractional (7/5), and implied probability — all in one place.
How odds conversion works
American odds show how much you win on a $100 stake (positive) or how much you must risk to win $100 (negative). Decimal odds are the total return per 1 unit staked, stake included. Fractional odds are the profit per unit staked: 3/2 means a $2 bet wins $3 profit. Implied probability is the break-even win rate the price is charging: 1 ÷ decimal.
Sportsbooks charge a vig that pushes implied probability above 100% across both sides. To find fair odds, run the two prices through our no-vig calculator.
Frequently asked questions
How do you convert American odds to decimal?+
For positive American odds: decimal = (odds / 100) + 1 → +140 becomes 2.40. For negative odds: decimal = (100 / |odds|) + 1 → −120 becomes 1.833. The converter does this instantly in either direction.
How do you convert American odds to implied probability?+
Negative odds: |odds| / (|odds| + 100) → −120 = 120/220 = 54.55%. Positive odds: 100 / (odds + 100) → +140 = 100/240 = 41.67%. Implied probability includes the sportsbook’s vig — to remove it, use our no-vig calculator.
What are decimal odds?+
Decimal odds show your total return per $1 wagered, including stake. 2.40 means a $1 winning bet returns $2.40 (profit + stake). Decimal is the standard format outside the US and is what most probability models use internally.
What is implied probability?+
The probability the sportsbook is pricing the bet at, derived from the odds. If the implied probability is 50% but the true probability is 55%, you have a 5% edge — that is the foundation of +EV betting.
Are these conversions accurate to multiple decimal places?+
Yes — decimals are shown to 3 places and probabilities to 2 places, which matches the precision used by Pinnacle and other sharp books. American odds are rounded to the nearest integer.
Calculators are free. The Turtle +EV picks platform runs every prop through a sport-specific model and ranks the ones where the line is mispriced. NBA · NHL · MLB · Soccer · Tennis. 48 books.