Betting odds are presented in three formats: decimal, fractional, and moneyline. They are three different ways of saying the exact same thing. Understanding the conversion between them is the first step to smart betting.
Decimal Odds (used in Europe, Australia): 2.50 means if you bet $100, you get $250 back (your $100 plus $150 profit). The number includes your original stake.
Fractional Odds (used in the UK): 3/2 means for every $2 you bet, you win $3. Your total return is $5 ($2 stake + $3 profit).
Moneyline Odds (used in the US): -150 means you must bet $150 to win $100. +200 means a $100 bet wins $200. Negative numbers are favourites, positive numbers are underdogs.
All three formats express the same implied probability. To convert:
Different bookmakers present odds in different formats. A bookmaker might offer 2.50 decimal while another offers 3/2 fractional. They are the same odds.
The real value comes from comparing implied probability to your personal probability estimate. If you think a team has a 45% chance of winning, but the bookmaker is only offering 40% implied probability (decimal odds of 2.50), that is a good bet. You are getting more return than the true probability warrants.
In 2026, most online sportsbooks show odds in decimal format by default, with options to switch to fractional or moneyline. Live betting odds change constantly as money flows in and out. A bet that had 2.50 odds five minutes ago might now be 2.40 because professional bettors have driven the probability up.
| Decimal | Fractional | Moneyline | Implied Probability |
|---|---|---|---|
| 1.50 | 1/2 | -200 | 66.7% |
| 2.00 | 1/1 | +100 | 50% |
| 2.50 | 3/2 | +150 | 40% |
| 3.00 | 2/1 | +200 | 33.3% |
Decimal is easiest for quick mental math. If you see 2.50, you immediately know your $100 bet returns $250. Fractional requires more calculation. Moneyline is confusing because negative and positive have different meanings.
Yes. A bet on Team A might be 2.50 at one bookmaker and 2.45 at another. This difference is called "line shopping." Professional bettors compare odds across multiple books to find the best return.
No. Implied probability is what the market thinks. The actual probability depends on real-world factors. The market also includes a "vig" (the bookmaker's cut), so implied probabilities across all outcomes of an event usually add up to more than 100%.
Verified against 0 primary sources. Last reviewed April 14, 2026.