Odds Converter Calculator: Instantly Convert Any Betting Odds Format

Different sportsbooks display odds in different formats—American (moneyline), Decimal (European), and Fractional (British). Our free odds converter instantly translates between all formats while showing you the implied probability behind any line.

What Are Betting Odds Formats?

Betting odds represent the payout you'll receive on a winning bet and the implied probability of that outcome occurring. The three main formats display this information differently.

Quick Answer: American odds show profit on $100 (like +150 or -200). Decimal odds show total return per $1 bet (like 2.50). Fractional odds show profit ratio (like 3/2). All represent the same probability—just different notation.

How to Use Our Free Odds Converter

Use the Odds Converter Calculator →

Enter odds in any format and instantly see conversions to all other formats plus implied probability.

Step-by-Step Instructions

1. Select Input Format: Choose American, Decimal, or Fractional

2. Enter the Odds: Type the odds value you want to convert

3. View All Conversions: See the equivalent in every format plus implied probability

4. Calculate Payouts (Optional): Enter a stake to see potential returns

Input Fields Explained

Field	Description	Example
Odds Format	Which format you're entering	American
Odds Value	The odds to convert	+150
Stake (Optional)	Amount to bet	$100

Understanding Each Odds Format

American Odds (Moneyline)

American odds use positive and negative numbers:

Positive odds (+150): Shows profit on a $100 bet

• +150 means $100 bet wins $150 profit ($250 total return)
• +300 means $100 bet wins $300 profit

Negative odds (-150): Shows how much to bet to win $100

• -150 means bet $150 to win $100 profit ($250 total return)
• -300 means bet $300 to win $100 profit

Decimal Odds (European)

Decimal odds show total return per unit staked:

• 2.50 means $1 returns $2.50 total (profit = $1.50)
• 1.50 means $1 returns $1.50 total (profit = $0.50)

Decimal odds always include your stake in the return. Favorites are below 2.00, underdogs are above 2.00.

Fractional Odds (British)

Fractional odds show profit relative to stake:

• 3/2 means win $3 for every $2 bet (profit = 1.5× stake)
• 1/4 means win $1 for every $4 bet (profit = 0.25× stake)

Read "3/2" as "three to two"—common in UK sports betting and horse racing.

Odds Conversion Formulas

American to Decimal

Positive American odds:

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

Negative American odds:

Decimal = (100 / |American|) + 1
Example: -150 → (100/150) + 1 = 1.667

Decimal to American

Decimal ≥ 2.00:

American = (Decimal - 1) × 100
Example: 2.50 → (2.50-1) × 100 = +150

Decimal < 2.00:

American = -100 / (Decimal - 1)
Example: 1.50 → -100 / (1.50-1) = -200

Fractional to Decimal

Decimal = (Numerator / Denominator) + 1
Example: 3/2 → (3/2) + 1 = 2.50

Implied Probability from Decimal

Implied Probability = 1 / Decimal Odds × 100%
Example: 2.50 → 1/2.50 = 40%

Quick Reference Conversion Chart

American	Decimal	Fractional	Implied Prob
+500	6.00	5/1	16.7%
+400	5.00	4/1	20.0%
+300	4.00	3/1	25.0%
+250	3.50	5/2	28.6%
+200	3.00	2/1	33.3%
+150	2.50	3/2	40.0%
+120	2.20	6/5	45.5%
+100	2.00	Evens	50.0%
-110	1.91	10/11	52.4%
-120	1.83	5/6	54.5%
-150	1.67	2/3	60.0%
-200	1.50	1/2	66.7%
-250	1.40	2/5	71.4%
-300	1.33	1/3	75.0%
-400	1.25	1/4	80.0%
-500	1.20	1/5	83.3%

Real-World Conversion Examples

Example 1: NFL Spread Odds

You see a spread at -110 American. What's this in other formats?

Conversion:

• American: -110
• Decimal: (100/110) + 1 = 1.909
• Fractional: 10/11
• Implied Probability: 52.4%

This means the book thinks there's about a 52.4% chance the spread hits (but charges juice on both sides).

Example 2: Soccer Match Odds

A European sportsbook shows a match at 3.40 decimal. What's this in American?

Conversion:

• Decimal: 3.40
• American: (3.40-1) × 100 = +240
• Fractional: 12/5
• Implied Probability: 29.4%

The team is roughly a 3-1 underdog.

Example 3: Horse Racing

UK bookmakers show a horse at 7/2 fractional. Convert it:

Conversion:

• Fractional: 7/2
• Decimal: (7/2) + 1 = 4.50
• American: (4.50-1) × 100 = +350
• Implied Probability: 22.2%

A $10 bet would return $45 ($35 profit + $10 stake).

Why Odds Conversion Matters

Compare Lines Across Sportsbooks

Different books use different formats. Bovada shows American, Bet365 shows Decimal, UK bookies show Fractional. Converting to one format lets you compare apples to apples.

Understand True Probability

Converting odds to implied probability reveals what the book "thinks" will happen. Compare this to your own probability estimate to find value.

Calculate Exact Payouts

Knowing how to convert ensures you understand exactly what you'll win. No surprises when your bet settles.

Communicate with Other Bettors

Betting communities use various formats. Being fluent in all three lets you discuss lines with anyone.

Common Odds Conversion Mistakes

1. Forgetting the Stake in Decimal: Decimal 2.50 doesn't mean "win 2.5×"—it means total return is 2.5× (profit is 1.5×).

2. Misreading American Favorites: -150 doesn't mean you lose $150. It means you risk $150 to win $100 profit.

3. Confusing Fractional Direction: 3/1 means win 3 for every 1 staked. 1/3 means win 1 for every 3 staked. Big difference!

4. Ignoring Vig in Probability: Implied probability from odds includes the book's margin. True probability is lower for favorites and higher for underdogs.

Frequently Asked Questions

Which odds format is best?

Decimal is mathematically simplest—just multiply by stake for total return. However, use whatever format your preferred sportsbook displays. Being fluent in all three is valuable.

Why do American odds have positive and negative?

The sign tells you who's favored. Negative means favorite (risk more to win less). Positive means underdog (risk less to win more). The break-even point is +100/-100.

What does "even money" mean?

Even money (+100 / 2.00 / 1/1) means a $100 bet wins $100 profit. The implied probability is 50%, meaning the book sees it as a true coin flip (before vig).

How do I calculate vig from odds?

Add the implied probabilities of all outcomes. If they sum to more than 100%, the excess is the vig. Example: -110 on both sides = 52.4% + 52.4% = 104.8% (4.8% vig).

Are decimal odds the same as "European odds"?

Yes, decimal odds are commonly called European odds because they're the standard format used in European sportsbooks. Same thing, different name.

Pro Tips for Working with Odds

• Memorize Common Lines: Know that -110 ≈ 1.91, -150 ≈ 1.67, +150 ≈ 2.50 without calculating

• Use Decimal for Quick Math: Decimal odds × stake = total return. Clean and simple.

• Convert to Probability for Analysis: Thinking in percentages (40% vs 35%) is more intuitive than comparing +150 to +185

• Check Multiple Books in Same Format: Convert everything to one format when line shopping

• Round Carefully: Rounding errors can accumulate. Use exact values for parlay calculations.

Related Betting Calculators

• Implied Probability Calculator - Deep dive into probability
• Parlay Calculator - Calculate multi-leg payouts
• Expected Value Calculator - Find +EV bets
• Hold/Vig Calculator - Analyze sportsbook margins
• Arbitrage Calculator - Find risk-free bets

Conclusion

Understanding odds formats is fundamental to sports betting success. Whether you're comparing lines across sportsbooks, calculating exact payouts, or analyzing implied probabilities, converting odds fluently is essential. Our free converter handles any format instantly.

Convert Any Odds Now →

Stop getting confused by different odds formats. Master the math behind betting lines and make more informed wagers with complete understanding of what you're betting.