How to Read Moneyline Odds: American, Decimal & Fractional Explained

Reading moneyline odds is the first step to understanding sports betting. Odds tell you three things: which team is favored to win, how much you risk, and how much you can win. Different regions use different formats, but they all communicate the same information.

This guide explains how to read American odds (used in the US), decimal odds (used in Europe and Canada), and fractional odds (used in the UK and Ireland). You will learn how to convert between formats, calculate implied probability, and avoid common mistakes when reading odds.

21+ only. Bet responsibly and only with money you can afford to lose.

Why Different Odds Formats Exist

Different regions developed different odds formats over time. American odds use plus and minus signs. Decimal odds use decimals (like 2.50). Fractional odds use fractions (like 3/2).

All three formats show the same information. The differences are cultural and historical, not mathematical. Understanding all three formats helps you bet internationally or compare odds across different sportsbooks.

Most US sportsbooks display American odds by default. Some allow you to switch to decimal or fractional in your account settings.

American Odds Explained (+ and -)

American odds are the most common format in the United States. They use positive and negative numbers to show favorites and underdogs.

Negative Odds (Favorites)

Negative odds tell you how much you must risk to win 100 dollars.

Example: -150

This means you risk 150 dollars to win 100 dollars in profit. Your total return is 250 dollars (your 150 dollar stake plus 100 dollars profit).

The bigger the negative number, the heavier the favorite. A team at -300 is a bigger favorite than a team at -150.

Positive Odds (Underdogs)

Positive odds tell you how much profit you win from a 100 dollar stake.

Example: +150

This means a 100 dollar bet wins 150 dollars in profit. Your total return is 250 dollars (your 100 dollar stake plus 150 dollars profit).

The bigger the positive number, the bigger the underdog. A team at +300 is a bigger underdog than a team at +150.

Pick'em or Even Odds (+100 or -100)

When both teams are roughly equal, you might see +100 or -100 on both sides. This means you risk 100 dollars to win 100 dollars. No vig (or minimal vig) is applied.

More often, you will see -110 on both sides. This adds the sportsbook margin (vig) and is the most common price for balanced markets.

Common American Odds Examples

Odds	Favorite or Underdog	What It Means
-400	Heavy favorite	Risk 400 to win 100
-200	Moderate favorite	Risk 200 to win 100
-150	Short favorite	Risk 150 to win 100
-110	Slight favorite or balanced	Risk 110 to win 100
+100	Even odds	Risk 100 to win 100
+150	Underdog	Risk 100 to win 150
+200	Bigger underdog	Risk 100 to win 200
+300	Big underdog	Risk 100 to win 300

For more on how American odds work in moneyline betting, see our Moneyline Betting Guide.

Decimal Odds Explained

Decimal odds are popular in Europe, Canada, and Australia. They show your total return (stake plus profit) per unit wagered.

Example: 2.50

This means for every 1 dollar you bet, you receive 2.50 dollars back if you win. Your profit is 1.50 dollars (2.50 total return minus 1 dollar stake).

How to Read Decimal Odds

Decimal odds are simple: multiply your stake by the odds to get your total return.

Example: You bet 100 dollars at 2.50 odds. Total return = 100 x 2.50 = 250 dollars Profit = 250 - 100 = 150 dollars

The lower the decimal, the bigger the favorite. Odds of 1.50 mean a heavy favorite. Odds of 4.00 mean a bigger underdog.

Common Decimal Odds Examples

Decimal Odds	Favorite or Underdog	Total Return on 100 Stake
1.25	Heavy favorite	125 (25 profit)
1.50	Moderate favorite	150 (50 profit)
1.67	Short favorite	167 (67 profit)
1.91	Slight favorite or balanced	191 (91 profit)
2.00	Even odds	200 (100 profit)
2.50	Underdog	250 (150 profit)
3.00	Bigger underdog	300 (200 profit)
4.00	Big underdog	400 (300 profit)

Decimal odds are easier for quick mental math than American odds. Many bettors prefer them for calculating parlay payouts.

Fractional Odds Explained

Fractional odds are traditional in the UK and Ireland. They show your profit relative to your stake as a fraction.

Example: 3/2 (read as three-to-two)

This means for every 2 dollars you stake, you win 3 dollars in profit. Your total return is 5 dollars (your 2 dollar stake plus 3 dollars profit).

How to Read Fractional Odds

The first number (numerator) is your profit. The second number (denominator) is your stake.

Example: 5/1 (five-to-one)

For every 1 dollar you stake, you win 5 dollars in profit. Total return is 6 dollars (1 dollar stake plus 5 dollars profit).

Example: 1/2 (one-to-two, also called two-to-one-on)

For every 2 dollars you stake, you win 1 dollar in profit. Total return is 3 dollars (2 dollar stake plus 1 dollar profit). This represents a favorite.

Common Fractional Odds Examples

Fractional Odds	Favorite or Underdog	Profit on 100 Stake
1/4	Heavy favorite	25
1/2	Moderate favorite	50
4/6 (or 2/3)	Short favorite	66.67
10/11	Slight favorite or balanced	90.91
1/1 (Evens)	Even odds	100
6/4 (or 3/2)	Underdog	150
2/1	Bigger underdog	200
3/1	Big underdog	300

Fractional odds can be confusing for beginners. Converting to decimal or American often makes the math clearer.

Converting Between Formats

American to Decimal

For negative American odds: Decimal = (100 / absolute value of odds) + 1

Example: -150 Decimal = (100 / 150) + 1 = 0.6667 + 1 = 1.67

For positive American odds: Decimal = (odds / 100) + 1

Example: +150 Decimal = (150 / 100) + 1 = 1.50 + 1 = 2.50

Decimal to American

For decimal odds less than 2.00 (favorites): American = -100 / (decimal - 1)

Example: 1.67 American = -100 / (1.67 - 1) = -100 / 0.67 = -149 (rounds to -150)

For decimal odds 2.00 or greater (underdogs or even): American = (decimal - 1) x 100

Example: 2.50 American = (2.50 - 1) x 100 = 1.50 x 100 = +150

Fractional to Decimal

Decimal = (numerator / denominator) + 1

Example: 3/2 Decimal = (3 / 2) + 1 = 1.50 + 1 = 2.50

Decimal to Fractional

Fractional = decimal - 1, then convert to simplest fraction

Example: 2.50 2.50 - 1 = 1.50 = 3/2

For more conversion help, use our odds converter tool (coming soon) or the calculator in our Moneyline Calculator Guide.

Calculating Implied Probability from Odds

Implied probability shows the likelihood of an outcome based on the odds. This helps you understand value and compare bets.

From American Odds

For negative odds: Implied probability = absolute value of odds / (absolute value of odds + 100)

Example: -150 Implied probability = 150 / (150 + 100) = 150 / 250 = 60%

For positive odds: Implied probability = 100 / (odds + 100)

Example: +150 Implied probability = 100 / (150 + 100) = 100 / 250 = 40%

From Decimal Odds

Implied probability = 1 / decimal odds

Example: 2.50 Implied probability = 1 / 2.50 = 0.40 = 40%

From Fractional Odds

Implied probability = denominator / (numerator + denominator)

Example: 3/2 Implied probability = 2 / (3 + 2) = 2 / 5 = 0.40 = 40%

Why Implied Probability Matters

Implied probabilities from both sides of a moneyline add up to more than 100%. The extra percentage is the sportsbook margin (vig).

Example: A moneyline of -110 / -110 has implied probabilities of about 52.4% each. Total: 104.8%. The extra 4.8% is the vig.

Understanding implied probability helps you spot value. If you believe a team has a 60% chance to win but the odds imply only 55%, you may have found a good bet.

For more on using implied probability in your betting strategy, see our Moneyline Betting Strategy Guide.

Real Examples (All Three Formats)

Let me show you the same bet in all three formats so you can see how they compare.

Example 1: Short Favorite

Kansas City Chiefs to win:

• American: -150
• Decimal: 1.67
• Fractional: 4/6 (or 2/3)
• Implied probability: 60%

What it means: Risk 150 dollars to win 100 dollars profit (or risk 1 dollar to win 0.67 dollars).

Example 2: Underdog

Denver Broncos to win:

• American: +200
• Decimal: 3.00
• Fractional: 2/1
• Implied probability: 33.3%

What it means: Risk 100 dollars to win 200 dollars profit (or risk 1 dollar to win 2 dollars).

Example 3: Heavy Favorite

Golden State Warriors to win:

• American: -400
• Decimal: 1.25
• Fractional: 1/4
• Implied probability: 80%

What it means: Risk 400 dollars to win 100 dollars profit (or risk 4 dollars to win 1 dollar).

Example 4: Big Underdog

Jacksonville Jaguars to win:

• American: +350
• Decimal: 4.50
• Fractional: 7/2
• Implied probability: 22.2%

What it means: Risk 100 dollars to win 350 dollars profit (or risk 2 dollars to win 7 dollars).

Which Format Should You Use?

The best format is the one you understand most easily. Here is guidance by situation:

Use American odds if:

• You bet primarily in the United States
• Your sportsbook defaults to American odds
• You are comfortable with positive/negative notation

Use decimal odds if:

• You want simple mental math
• You are calculating parlay payouts
• You bet internationally or at European sportsbooks

Use fractional odds if:

• You are betting in the UK or Ireland
• You are familiar with horse racing odds
• Your sportsbook uses fractions by default

Most US sportsbooks let you toggle between formats in your account settings. Try all three and pick the one that makes the most sense to you.

Common Mistakes Reading Odds

Confusing Profit vs Total Return

American and fractional odds show profit. Decimal odds show total return (stake plus profit).

Example: +150 (American) = 2.50 (decimal)

• American: 100 dollar bet wins 150 dollars profit
• Decimal: 100 dollar bet returns 250 dollars total (including your 100 dollar stake)

Always check whether the number you see is profit or total return.

Misreading Negative Odds

Negative odds do not mean you lose money. They mean you risk more to win less because the team is favored.

Example: -200 does not mean you lose 200 dollars. It means you risk 200 dollars to win 100 dollars profit.

Forgetting the Vig

Implied probabilities from both sides of a market add up to more than 100%. Do not assume a 60% implied probability means a 60% true chance to win. The sportsbook margin inflates the probability.

To find fair probability, you need to remove the vig. For more on no-vig odds, see our Moneyline Betting Strategy Guide.

Mixing Up Fractional Odds

1/2 is not the same as 2/1. Always check which number is first.

• 1/2 = favorite (risk 2 to win 1)
• 2/1 = underdog (risk 1 to win 2)

When in doubt, convert to decimal or American for clarity.

Frequently Asked Questions

What does +150 mean in betting?

+150 is American odds for an underdog. A 100 dollar bet wins 150 dollars in profit. Your total return is 250 dollars (100 dollar stake plus 150 dollars profit).

What does -110 mean in betting?

-110 is American odds for a slight favorite or balanced market. You risk 110 dollars to win 100 dollars in profit. This is the most common price for spread bets.

How do I convert American odds to decimal?

For negative odds: (100 / absolute value) + 1. For positive odds: (odds / 100) + 1. Example: -150 converts to 1.67. +150 converts to 2.50.

How do I calculate payout from odds?

For American odds: Use the formulas above or multiply your stake by the conversion to decimal. For decimal odds: Multiply your stake by the decimal. For fractional odds: Multiply your stake by (numerator / denominator), then add your stake.

Are decimal odds better than American odds?

Neither is better. Decimal odds are easier for quick mental math. American odds clearly show favorites (negative) vs underdogs (positive). Use whichever format you find clearest.

Why do sportsbooks use different odds formats?

Cultural and historical reasons. American odds developed in the US. Decimal odds developed in Europe. Fractional odds developed in the UK. All three show the same information.

Can I change the odds format on my sportsbook app?

Most US sportsbooks allow you to toggle between American, decimal, and fractional in your account settings. Check your app preferences or settings menu.

How do I know if I am getting good odds?

Compare the implied probability to your estimated probability. If the implied probability is lower than your estimate, you may have found value. Always shop odds across multiple sportsbooks.