Free Odds Converter

How to Use This Converter

Enter a value in any of the four fields above and the other three will update instantly. You can type American odds like -110 or +200, decimal odds like 1.91 or 3.00, fractional odds like 10/11 or 5/2, or an implied probability percentage like 52.4.

Use the quick-fill buttons to jump to common odds values. The converter handles everything from heavy favorites (-500 and beyond) to long shots (+10000) with full precision.

Understanding Odds Formats

American Odds

American odds use a positive or negative number relative to $100. Negative odds (like -110) tell you how much you need to bet to win $100 in profit. Positive odds (like +200) tell you how much profit you earn on a $100 bet. American odds are the standard format at US sportsbooks including DraftKings, FanDuel, and BetMGM.

Decimal Odds

Decimal odds represent the total payout per $1 wagered, including your original stake. Multiply your bet by the decimal odds to calculate your total return. For example, a $50 bet at 2.50 pays $125 total ($75 profit + $50 stake). Decimal odds are popular in Europe, Australia, and Canada because they make payout math simple and work for both favorites and underdogs without special rules.

Fractional Odds

Fractional odds show profit relative to stake. Odds of 5/2 mean you win $5 for every $2 wagered. The numerator is your potential profit and the denominator is the amount you risk. Fractional odds are the traditional format in the UK and Ireland, commonly used in horse racing. Odds of 1/1 (also called "evens") mean you double your money.

Implied Probability

Implied probability converts odds into a percentage that represents how likely the sportsbook considers an outcome. This is the most useful format for finding value bets. If you believe a team has a 55% chance of winning but the odds imply only 48%, that is a potential value bet. Keep in mind that the sum of implied probabilities in a market exceeds 100% because of the sportsbook's built-in margin (vig).

Odds Conversion Formulas

All odds formats express the same underlying ratio between risk and reward. Here are the conversion formulas using decimal odds as the common intermediate:

American to Decimal: For negative odds, use 1 + (100 / |American|). For positive odds, use 1 + (American / 100). Example: -110 becomes 1 + (100/110) = 1.909.

Decimal to American: If decimal is 2.00 or higher, American = (Decimal - 1) × 100. If under 2.00, American = -100 / (Decimal - 1). Example: 3.00 becomes (3 - 1) × 100 = +200.

Decimal to Implied Probability: Divide 1 by the decimal odds, then multiply by 100. Example: 1 / 1.909 × 100 = 52.4%.

Decimal to Fractional: Subtract 1 from the decimal odds and express the result as a fraction. Example: 2.50 - 1 = 1.5 = 3/2.

Quick Reference Chart

Related Tools & Guides

Now that you understand odds formats, explore these resources:

• Parlay Calculator — Combine multiple odds into a parlay and see your total payout.
• EV Calculator — Use implied probability to check if a bet has positive expected value.
• Bankroll Calculator — Size your bets based on your bankroll.
• Understanding Odds, Spreads, and Lines — Our complete beginner guide.
• NFL Moneyline Guide · NBA Moneyline Guide — Moneyline strategy by sport.