Odds Converter Calculator: Convert All Betting Odds

An odds converter calculator is the fastest way to translate betting odds between American, decimal, and fractional formats while instantly seeing the implied probability behind any line. Whether you are comparing odds across multiple sportsbooks, building a betting tracker in Excel, or simply trying to understand what -150 or +200 actually means, this tool does the heavy lifting for you.

Sports betting in the United States primarily uses American odds, but international books and certain markets display decimal or fractional formats. Our free odds converter calculator handles all three formats in one place, showing you exactly what the numbers mean and what win probability the sportsbook is pricing into each line. This matters because understanding implied probability is the first step toward identifying whether a bet offers real value.

If you are new to odds formats and want to understand the math behind conversions, start with our complete guide to converting betting odds. For a deeper dive into what implied probabilities reveal about value betting, explore our implied probability calculator and strategy guides.

Important: This calculator shows theoretical probabilities and potential payouts based on the odds you enter. It does not guarantee any outcome. Sports betting involves real financial risk, and you should only wager amounts you can afford to lose. Betting should remain entertaining. If it ever feels like a problem, resources are available to help.

Odds Converter Calculator - Quick Start

The odds converter calculator below lets you instantly convert any betting odds format to all others while displaying the implied probability. This is the primary tool you need for comparing lines across sportsbooks, understanding what odds mean in practical terms, and making informed betting decisions.

What this calculator does:

• Converts American odds (like -110, +200) to decimal and fractional formats
• Converts decimal odds (like 2.00, 3.50) to American and fractional formats
• Converts fractional odds (like 5/2, 10/1) to American and decimal formats
• Shows implied probability for any odds you enter
• Calculates potential payout based on your stake amount

The calculator is designed for US-based sports bettors using legal, regulated sportsbooks. All examples and default settings use American odds since that is the standard format at US books like DraftKings, FanDuel, BetMGM, and Caesars. However, the tool works equally well for bettors who prefer decimal or fractional formats.

How to get started:

1. Select your starting odds format (American, decimal, or fractional)
2. Enter the odds you want to convert
3. Optionally add a stake amount to see potential payouts
4. View all converted formats and implied probability instantly

The implied probability percentage tells you what win rate you need to break even at those odds over the long run. For example, if you see 50% implied probability, you need to win half your bets at those odds just to break even. Understanding this number is essential for evaluating whether a bet offers value.

How the Odds Converter Works (Formats and Outputs)

The odds converter calculator supports three primary odds formats plus implied probability. When you enter odds in any single format, the tool automatically calculates and displays the equivalent values in all other formats. This eliminates manual math and reduces the risk of conversion errors.

Supported formats:

• American odds: The standard format at US sportsbooks. Positive numbers (+150) show profit on a $100 stake. Negative numbers (-150) show how much you must risk to win $100.
• Decimal odds: Common internationally and increasingly used in US markets. The number represents your total return per $1 wagered, including your original stake.
• Fractional odds: Traditional format for horse racing and UK markets. Shows profit relative to stake as a ratio (5/2 means $5 profit for every $2 wagered).
• Implied probability: The percentage chance of winning that the odds represent. Calculated directly from the odds without accounting for the sportsbook margin (vig).

How the conversion works:

When you enter -150 American odds, the calculator determines that this represents a 60% implied probability, 1.67 decimal odds, and approximately 2/3 fractional odds. All four values represent the same underlying price. The only difference is how they are displayed.

Understanding each output field:

• Odds fields: Show the same price in different formats for comparison and reference
• Stake field: Your bet amount (optional, used to calculate payout)
• Potential payout: Your stake multiplied by the odds, showing total return including stake
• Implied probability: The breakeven win rate embedded in the odds

A note about vig: The implied probability shown is based on the stated odds only. Sportsbooks build a margin (called vig or juice) into their odds, which means the implied probabilities on both sides of a two-way market typically add up to more than 100%. The converter shows you what each individual line implies, but identifying true fair value requires comparing implied probabilities to your own estimated probabilities.

Converting American Odds

American odds are the default format at every major US sportsbook. Understanding how to convert them is essential for comparing lines and calculating value. The format uses positive and negative numbers to indicate underdogs and favorites respectively.

Positive American odds (+200, +150, etc.):

Positive odds show how much profit you win on a $100 stake. Odds of +200 mean a $100 bet returns $200 in profit plus your $100 stake back, for a total payout of $300.

Negative American odds (-150, -110, etc.):

Negative odds show how much you must risk to win $100 in profit. Odds of -150 mean you risk $150 to win $100 profit, for a total payout of $250.

Converting American to decimal:

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

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

Examples:

American Odds	Decimal Odds	Fractional Odds	Implied Probability
+200	3.00	2/1	33.3%
+150	2.50	3/2	40.0%
+100 (Even)	2.00	1/1	50.0%
-110	1.91	10/11	52.4%
-150	1.67	2/3	60.0%
-200	1.50	1/2	66.7%

Real-world example - NFL moneyline:

The Kansas City Chiefs are favored at -180 against the Las Vegas Raiders at +155. Using the converter:

• Chiefs -180 = 1.56 decimal = 5/9 fractional = 64.3% implied probability
• Raiders +155 = 2.55 decimal = 31/20 fractional = 39.2% implied probability

Notice the combined implied probability is 103.5%, not 100%. That extra 3.5% represents the sportsbook margin (vig) built into both sides.

For a detailed breakdown of American odds mechanics, see our American odds explained guide.

Converting Decimal Odds

Decimal odds show your total return per unit wagered, including your original stake. A decimal odds of 2.50 means a $10 bet returns $25 total ($15 profit plus $10 stake). This format is popular internationally and is especially useful for parlay calculations because you simply multiply decimal odds together.

Converting decimal to American:

For decimal odds 2.00 or higher (underdogs): American = (Decimal - 1) x 100

For decimal odds below 2.00 (favorites): American = -100 / (Decimal - 1)

Examples:

Decimal Odds	American Odds	Fractional Odds	Implied Probability
4.00	+300	3/1	25.0%
3.00	+200	2/1	33.3%
2.00	+100	1/1	50.0%
1.80	-125	4/5	55.6%
1.50	-200	1/2	66.7%
1.25	-400	1/4	80.0%

Why decimal odds matter for parlays:

When building a parlay or Same Game Parlay, decimal odds let you calculate the combined odds by simple multiplication. A 3-leg parlay with decimal odds of 1.90, 2.10, and 1.75 has combined decimal odds of 1.90 x 2.10 x 1.75 = 6.98. Convert that back to American (+598) to see what it means in familiar terms.

This multiplication approach is much simpler than the American odds conversion formulas required to combine multiple legs. Many sharp bettors prefer to work in decimal format for this reason, even when betting at US sportsbooks.

For more on decimal odds and when to use them, see our decimal odds explained guide.

Converting Fractional Odds

Fractional odds show profit relative to stake as a ratio. Odds of 5/2 mean you profit $5 for every $2 wagered. This format dominates horse racing and UK betting markets but appears less frequently at mainstream US sportsbooks.

Reading fractional odds:

The left number (numerator) is your profit. The right number (denominator) is your stake. Odds of 10/1 mean $10 profit per $1 stake. Odds of 1/4 mean $1 profit per $4 stake.

Converting fractional to decimal:

Decimal = (Numerator / Denominator) + 1

Fractional 5/2 = (5/2) + 1 = 2.5 + 1 = 3.50 decimal

Converting fractional to American:

For fractions greater than or equal to 1/1: American = (Numerator / Denominator) x 100

For fractions less than 1/1: American = -100 / (Numerator / Denominator)

Common fractional odds and equivalents:

Fractional Odds	Decimal Odds	American Odds	Implied Probability
10/1	11.00	+1000	9.1%
5/1	6.00	+500	16.7%
5/2	3.50	+250	28.6%
2/1	3.00	+200	33.3%
1/1 (Evens)	2.00	+100	50.0%
1/2	1.50	-200	66.7%
1/4	1.25	-400	80.0%

Kentucky Derby example:

A horse listed at 15/1 to win the Kentucky Derby has decimal odds of 16.00 and American odds of +1500. The implied probability is 6.25%, meaning the sportsbook prices this horse with roughly a 1-in-16 chance of winning.

If you bet $20 on that horse and it wins, you profit $300 (15 x $20) plus receive your $20 stake back for a total payout of $320.

For more on fractional odds in horse racing and other markets, see our fractional odds explained guide.

Converting Moneyline Odds to Implied Probability

Implied probability is the percentage chance of winning that the odds represent. This is arguably the most important conversion because it translates abstract odds numbers into something intuitively meaningful. When you see -150 odds, knowing that equals 60% implied probability helps you evaluate whether the bet offers value based on your own analysis.

Why implied probability matters:

• It shows the breakeven win rate for a bet at those odds
• It helps you compare your estimated probability to the sportsbook price
• It reveals the sportsbook margin when you add implied probabilities across all outcomes
• It provides a common language for comparing bets across different odds formats

Converting American odds to implied probability:

For positive American odds: Implied Probability = 100 / (American + 100)

For negative American odds: Implied Probability = |American| / (|American| + 100)

Step-by-step examples:

Example 1: Underdog at +200

The formula is 100 / (200 + 100) = 100 / 300 = 0.333 = 33.3%

This means you need to win 33.3% of your bets at +200 odds to break even over time. If you believe the true probability is higher than 33.3%, the bet offers positive expected value.

Example 2: Favorite at -150

The formula is 150 / (150 + 100) = 150 / 250 = 0.60 = 60.0%

You need to win 60% of your bets at -150 to break even. If you estimate the favorite has a 65% chance of winning, this bet has value. If you estimate 55%, it does not.

Real NBA example:

The Boston Celtics are -180 favorites against the Miami Heat at +155.

• Celtics: 180 / (180 + 100) = 180 / 280 = 64.3% implied probability
• Heat: 100 / (155 + 100) = 100 / 255 = 39.2% implied probability
• Combined: 64.3% + 39.2% = 103.5%

The combined 103.5% reflects the sportsbook margin. If both outcomes had a fair price, they would total 100%. The extra 3.5% is the vig the book captures regardless of outcome.

Moneyline Odds	Implied Probability	Breakeven Win Rate
+300	25.0%	Win 1 in 4
+200	33.3%	Win 1 in 3
+150	40.0%	Win 2 in 5
+100	50.0%	Win 1 in 2
-110	52.4%	Win 11 in 21
-150	60.0%	Win 3 in 5
-200	66.7%	Win 2 in 3
-300	75.0%	Win 3 in 4

For detailed strategy on using implied probability to find value, see our implied probability in sports betting guide.

Convert Odds to Percentage (Implied Probability)

Converting any odds format to a percentage follows consistent formulas. The goal is always the same: determine what probability the odds represent so you can compare it to your own estimate.

American odds to percentage:

Positive: Percentage = 100 / (Odds + 100) x 100

Negative: Percentage = |Odds| / (|Odds| + 100) x 100

Decimal odds to percentage:

Percentage = (1 / Decimal) x 100

Example: Decimal 2.50 = (1 / 2.50) x 100 = 40%

Fractional odds to percentage:

Percentage = Denominator / (Numerator + Denominator) x 100

Example: Fractional 3/2 = 2 / (3 + 2) x 100 = 2 / 5 x 100 = 40%

Quick reference for common conversions:

• +100 = 50%
• +200 = 33.3%
• +300 = 25%
• -100 = 50%
• -150 = 60%
• -200 = 66.7%
• -300 = 75%

While these formulas are straightforward, the odds converter calculator eliminates the need for manual math. Enter any odds and instantly see the implied probability without worrying about which formula applies.

For more depth on implied probability calculations and applications, use our dedicated implied probability calculator.

Convert Probability Back to Odds

Sometimes you want to work in the opposite direction. If you estimate a team has a 55% chance of winning, what American odds should you be looking for to find value?

Probability to American odds:

For probabilities below 50%: American = (100 / Probability) - 100 (use positive result)

For probabilities above 50%: American = (Probability / (1 - Probability)) x (-100) (use negative result)

Example: You estimate 55% probability

55 / (1 - 0.55) x (-100) = 55 / 0.45 x (-100) = -122.2

Your estimated fair odds are approximately -122. If the sportsbook offers -110, you have an edge because the book is offering better odds than your estimated fair value.

Example: You estimate 40% probability

(100 / 0.40) - 100 = 250 - 100 = +150

Your estimated fair odds are +150. If the sportsbook offers +180, you have value because the potential return exceeds what the true probability warrants.

Probability to decimal odds:

Decimal = 100 / Probability

Example: 40% probability = 100 / 40 = 2.50 decimal

Important caveat:

These calculations show theoretical fair odds without any margin. Sportsbooks always include vig, meaning the actual odds offered will be worse than theoretical fair value. Finding value requires odds that exceed your estimated fair price even after accounting for the sportsbook edge.

Betting Odds Formulas in Excel and Google Sheets

Many bettors track their bets and calculate odds in spreadsheets. Having the right formulas saves time and reduces errors when analyzing lines or building betting models.

American odds to implied probability:

For positive odds in cell A1: =100/(A1+100)

For negative odds in cell A1: =ABS(A1)/(ABS(A1)+100)

Combined formula that handles both: =IF(A1 greater than 0, 100/(A1+100), ABS(A1)/(ABS(A1)+100))

American odds to decimal:

For positive odds: =(A1/100)+1

For negative odds: =(100/ABS(A1))+1

Combined formula: =IF(A1 greater than 0, (A1/100)+1, (100/ABS(A1))+1)

Decimal odds to implied probability:

=1/A1

Decimal odds to American:

=IF(A1 greater than or equal to 2, (A1-1)*100, -100/(A1-1))

Probability to American odds:

=IF(A1 less than 0.5, (100/A1)-100, -(A1/(1-A1))*100)

Setting up a conversion spreadsheet:

Create columns for:

• Input odds (A)
• Implied probability (B)
• Decimal odds (C)
• American odds (D)
• Stake (E)
• Potential payout (F)
• Profit (G)

Sample row formulas (assuming American odds input in A2):

• B2: =IF(A2 greater than 0, 100/(A2+100), ABS(A2)/(ABS(A2)+100))
• C2: =IF(A2 greater than 0, (A2/100)+1, (100/ABS(A2))+1)
• D2: =A2 (if American input) or convert from decimal
• F2: =E2*C2
• G2: =F2-E2

Conversion	Excel/Sheets Formula	Notes
American to Implied %	=IF(A1 greater than 0, 100/(A1+100), ABS(A1)/(ABS(A1)+100))	Returns decimal; multiply by 100 for percentage
American to Decimal	=IF(A1 greater than 0, (A1/100)+1, (100/ABS(A1))+1)	Works for both positive and negative odds
Decimal to Implied %	=1/A1	Simple division; multiply by 100 for percentage
Decimal to American	=IF(A1 greater than or equal to 2, (A1-1)*100, -100/(A1-1))	Handles favorites and underdogs
Probability to American	=IF(A1 less than 0.5, (100/A1)-100, -(A1/(1-A1))*100)	Input as decimal (0.55 not 55%)

These formulas let you build a custom betting tracker that automatically converts odds and calculates expected value as you enter data.

Sample spreadsheet setup:

Here is how a simple conversion tracker might look with formulas applied:

Game	American Odds	Decimal	Implied %	Your Est. %	Edge?
Chiefs ML	-150	1.67	60.0%	65%	Yes (+5%)
Lakers ML	+140	2.40	41.7%	38%	No (-3.7%)
Yankees ML	-110	1.91	52.4%	55%	Yes (+2.6%)

The "Edge" column shows the difference between your estimated probability and the implied probability. Positive edges indicate potential value. Building this type of tracker helps you systematically identify and record betting opportunities rather than relying on gut instinct.

Download resources:

To save time setting up your own spreadsheet, you can use pre-built templates that include all the conversion formulas ready to go. Look for templates that include columns for tracking your estimated probabilities alongside the implied probabilities so you can identify value bets at a glance.

Printable Odds Conversion Chart

A quick-reference odds conversion chart is useful for line shopping and on-the-fly comparisons when you do not have access to a calculator. Print or bookmark this chart for common odds values.

Most common American odds and conversions:

American	Decimal	Fractional	Implied %
+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%
+175	2.75	7/4	36.4%
+150	2.50	3/2	40.0%
+125	2.25	5/4	44.4%
+110	2.10	11/10	47.6%
+100	2.00	1/1	50.0%
-105	1.95	20/21	51.2%
-110	1.91	10/11	52.4%
-115	1.87	20/23	53.5%
-120	1.83	5/6	54.5%
-130	1.77	10/13	56.5%
-140	1.71	5/7	58.3%
-150	1.67	2/3	60.0%
-175	1.57	4/7	63.6%
-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%

How to use the chart:

• When line shopping, quickly reference equivalent odds across formats
• Identify the breakeven win rate for any line
• Compare sportsbook prices by converting to a common format
• Estimate parlay payouts by mentally combining decimal odds

Keep this chart accessible when browsing odds at multiple sportsbooks or building parlays on mobile.

Get the PDF version:

For offline reference, save or print this conversion chart as a PDF. Having a physical or saved copy means you can check conversions even when you do not have internet access or prefer not to use your phone during a game.

How to Use the Odds Converter Calculator Step by Step

Follow this simple walkthrough to get accurate conversions every time using the OddsIndex odds converter calculator.

Step 1: Choose your starting format

Select whether you are entering American, decimal, or fractional odds. American is the default since it is standard at US sportsbooks. If you are converting odds from an international book or a horse racing market, select the appropriate format.

Step 2: Enter your odds

Type the odds exactly as you see them on your sportsbook. For American odds, include the sign (+ or -). For decimal odds, enter the number with decimals (like 2.50). For fractional odds, use the slash format (like 5/2).

Step 3: Add an optional stake amount

If you want to see potential payouts, enter your intended bet amount. This is optional. The conversion works without a stake, but entering one shows you exactly what you stand to win.

Step 4: Review all converted values

The calculator instantly displays:

• Equivalent odds in all three formats
• Implied probability as a percentage
• Potential payout (if stake entered)
• Profit amount (if stake entered)

Step 5: Interpret the results

Use the implied probability to evaluate whether the bet offers value. Compare the converted odds across formats when shopping lines at different sportsbooks. Check the potential payout to confirm the risk/reward matches your expectations.

Worked example 1: Betting a favorite

You see the Philadelphia Eagles at -150 moneyline. Enter -150 in American format.

Results:

• Decimal: 1.67
• Fractional: 2/3
• Implied probability: 60.0%

If you enter a $50 stake:

• Potential payout: $83.33
• Profit: $33.33

The 60% implied probability means you need the Eagles to win 60% of games at these odds to break even. If you believe they have a 65%+ chance based on your analysis, this bet has value.

Worked example 2: Betting a longshot futures pick

You want to bet the Miami Dolphins at +2500 to win the Super Bowl. Enter +2500 in American format.

Results:

• Decimal: 26.00
• Fractional: 25/1
• Implied probability: 3.85%

If you enter a $20 stake:

• Potential payout: $520
• Profit: $500

The 3.85% implied probability means the book prices Miami with roughly a 1-in-26 chance. This is a high-risk, high-reward bet suitable only for entertainment value unless you have specific reasons to believe the true probability exceeds 4%.

Using the converter for live betting:

During live games, odds shift rapidly. The converter helps you quickly assess whether an in-game line offers value by showing the implied probability in real time. If a team is +180 live and you believe they have a 40% chance, enter +180 to see the 35.7% implied probability. The gap between 40% and 35.7% represents potential value.

Live betting requires fast decisions. Having the converter open on a second screen or browser tab lets you check lines instantly as they change. Many live bettors keep the calculator visible throughout the game, entering new odds as they appear to identify moments when the in-game price diverges significantly from their real-time assessment of the situation.

Using the converter for line shopping:

Line shopping means comparing the same bet across multiple sportsbooks to find the best price. The odds converter makes this process easier by translating all lines to a common format for direct comparison.

For example, you want to bet the Buffalo Bills moneyline. You check three sportsbooks:

• Book A: -145
• Book B: -140
• Book C: -138

Converting each to implied probability:

• Book A: 59.2%
• Book B: 58.3%
• Book C: 58.0%

Book C offers the best value with the lowest implied probability. Over time, consistently taking the best available line compounds into significant savings. Even small differences like -138 versus -145 add up across hundreds of bets.

Visit our full-screen odds converter calculator for a dedicated tool experience with larger inputs and easier mobile use.

Using Odds Conversion for Parlays, SGPs and Longshots

Understanding odds conversion becomes especially useful when building multi-leg bets like parlays and Same Game Parlays (SGPs). Decimal odds make parlay math simple, and implied probabilities reveal just how unlikely your parlay is to hit.

Why decimal odds work best for parlays:

To calculate parlay odds, you multiply the decimal odds of each leg. This is much simpler than converting American odds through complex formulas.

3-leg parlay example:

• Leg 1: Chiefs -110 = 1.91 decimal
• Leg 2: Lakers -140 = 1.71 decimal
• Leg 3: Yankees +120 = 2.20 decimal

Combined decimal odds: 1.91 x 1.71 x 2.20 = 7.19

Convert 7.19 decimal back to American: +619

A $10 bet returns $71.90 total ($61.90 profit).

Implied probability of a parlay:

Multiply the implied probabilities of each leg:

• Chiefs: 52.4%
• Lakers: 58.3%
• Yankees: 45.5%

Combined: 0.524 x 0.583 x 0.455 = 13.9%

Your 3-leg parlay has approximately a 14% chance of hitting. This is why parlays are high-risk bets. Even with three favorites or near-even legs, the combined probability drops dramatically.

How small odds changes compound:

Scenario	Leg Odds (American)	Combined Decimal	Combined Implied %
2 legs at -110	-110, -110	3.65	27.4%
3 legs at -110	-110, -110, -110	6.97	14.4%
4 legs at -110	-110, -110, -110, -110	13.31	7.5%
5 legs at -110	Five -110 legs	25.41	3.9%

Each additional leg roughly halves your win probability, even when all legs are standard -110 lines.

Same Game Parlay considerations:

SGPs combine multiple outcomes from the same game, which means the selections may be correlated. For example, betting a quarterback to throw 300+ yards AND his team to win is positively correlated. If he throws that many yards, the team is more likely winning.

Sportsbooks adjust SGP odds to account for correlations, which is why SGP payouts often differ from what a standard parlay calculator shows. Use the converter to understand baseline probabilities, but recognize that SGP-specific pricing reflects the book's correlation models.

For detailed parlay strategy, see our parlay betting guide and use our parlay calculator to build multi-leg bets.

Common Mistakes When Converting Betting Odds

Even experienced bettors make conversion errors that lead to miscalculated payouts or misunderstood probabilities. Here are the most common mistakes and how to avoid them.

Mistake 1: Confusing positive and negative American odds

Positive odds (+150) mean you are betting on an underdog. Negative odds (-150) mean you are betting on a favorite. Mixing these up completely changes the implied probability.

• +150 = 40% implied probability (underdog)
• -150 = 60% implied probability (favorite)

How to avoid it: Always check the sign before entering odds. If unsure whether a team is favored, the negative number is the favorite.

Mistake 2: Forgetting about vig when evaluating implied probability

The implied probability from odds includes the sportsbook margin. When both sides of a market add up to more than 100%, the excess is vig.

• Side A: -110 = 52.4%
• Side B: -110 = 52.4%
• Total: 104.8%

The extra 4.8% is vig. Neither side truly has a 52.4% chance. The real fair odds would be closer to 50/50.

How to avoid it: Remove vig by normalizing probabilities. Divide each implied probability by the total to get vig-free probabilities. Or use our implied probability calculator which shows vig-adjusted numbers.

Mistake 3: Misreading fractional odds direction

Fractional odds of 5/2 and 2/5 are very different. 5/2 is an underdog (you profit $5 per $2 wagered). 2/5 is a heavy favorite (you profit $2 per $5 wagered).

• 5/2 = +250 American = 28.6% implied
• 2/5 = -250 American = 71.4% implied

How to avoid it: Remember that the larger number on top means underdog odds. Use the converter if ever uncertain.

Mistake 4: Relying on mental math for complex conversions

Rough estimates work for simple odds but fail with less common numbers. Mental math often leads to errors that affect your bet sizing and value assessment.

How to avoid it: Use the calculator for every conversion. It takes seconds and eliminates human error.

Mistake 5: Not converting when line shopping

Different sportsbooks may display odds in different default formats. If you do not convert to a common format, you might miss that one book offers significantly better value.

How to avoid it: Convert all lines to the same format (decimal is easiest for direct comparison) before deciding where to place your bet.

Mistake 6: Ignoring the payout field

Some bettors focus only on odds conversion without checking the actual dollar payout. This can lead to misunderstanding how much you stand to win or lose.

How to avoid it: Always enter your intended stake and review the payout field. Make sure the risk/reward ratio matches your expectations before betting.

Mistake 7: Assuming all sportsbooks display odds the same way

Most US sportsbooks default to American odds, but some show decimal by default or allow users to switch formats in settings. If you copy odds from one source without checking the format, you might enter decimal odds into an American odds field or vice versa.

How to avoid it: Confirm the odds format before entering. American odds always have a + or - sign. Decimal odds are typically between 1.01 and 100+ with no sign. Fractional odds use a slash (like 5/2).

Mistake 8: Not double-checking unusual odds values

If you see odds that seem unusually high or low, there may be a typo or you may be looking at a different market than expected. Entering +2500 when the actual line is +250 produces wildly different implied probabilities.

How to avoid it: Sanity-check your conversions. If the implied probability seems off compared to your expectations for the matchup, verify you entered the correct odds from the sportsbook.

Frequently Asked Questions

How do you convert betting odds?

To convert betting odds, use formulas that translate between American, decimal, and fractional formats. For American to decimal: if positive, divide by 100 and add 1; if negative, divide 100 by the absolute value and add 1. For implied probability from American odds: if positive, divide 100 by (odds + 100); if negative, divide the absolute value by (absolute value + 100). The easiest approach is using an odds converter calculator that handles all conversions instantly.

How do you convert American odds to decimal?

For positive American odds like +200, divide by 100 and add 1: (200/100) + 1 = 3.00 decimal. For negative American odds like -150, divide 100 by the absolute value and add 1: (100/150) + 1 = 1.67 decimal. This formula works for any American odds value.

How do you convert odds to percentage?

To convert odds to implied probability percentage, use these formulas. For positive American odds: 100 / (odds + 100). So +200 becomes 100/300 = 33.3%. For negative American odds: absolute value / (absolute value + 100). So -150 becomes 150/250 = 60%. For decimal odds, simply calculate 1 / decimal odds. So 2.50 becomes 1/2.5 = 40%.

How do you convert probability to odds?

To convert a probability to American odds: if below 50%, calculate (100 / probability) - 100 for positive odds; if above 50%, calculate (probability / (1 - probability)) x (-100) for negative odds. For example, 40% probability converts to (100/0.40) - 100 = +150. And 60% probability converts to (0.60/0.40) x (-100) = -150.

What does plus 200 mean in betting?

Plus 200 (+200) means you are betting on an underdog and will profit $200 for every $100 wagered if your bet wins. Your total return would be $300 ($200 profit plus your $100 stake). In decimal format, +200 equals 3.00. The implied probability is 33.3%, meaning the sportsbook prices this outcome with roughly a 1-in-3 chance of occurring.

What does minus 150 odds mean?

Minus 150 (-150) means you are betting on a favorite and must risk $150 to win $100 in profit. Your total return would be $250 ($100 profit plus your $150 stake). In decimal format, -150 equals 1.67. The implied probability is 60%, meaning the sportsbook prices this outcome with a 60% chance of occurring.

What is the betting odds formula in Excel?

For American odds to implied probability in Excel, use: =IF(A1 greater than 0, 100/(A1+100), ABS(A1)/(ABS(A1)+100)) where A1 contains the American odds. For American to decimal: =IF(A1 greater than 0, (A1/100)+1, (100/ABS(A1))+1). For decimal to American: =IF(A1 greater than or equal to 2, (A1-1) times 100, -100/(A1-1)). These formulas handle both favorites and underdogs automatically.

How can I use implied probability to find value bets?

Implied probability reveals value when compared to your own estimated probability. Convert the sportsbook odds to implied probability, then compare to your analysis. If you estimate a team has a 55% chance of winning but the odds imply only 50%, you have found potential value because the true probability exceeds what the price suggests. Over time, consistently betting when your estimated probability exceeds implied probability leads to positive expected value.

Responsible Gambling Notice

Sports betting involves real money and real risk. No calculator, converter, or strategy guarantees winning bets. The odds converter shows theoretical probabilities and potential payouts based on the numbers you enter, but actual outcomes depend on unpredictable events.

Key principles for responsible betting:

• Only bet amounts you can afford to lose entirely
• Set a budget before you start and stick to it
• Never chase losses with larger bets
• Take breaks and step away if betting stops being fun
• Recognize that the house edge means most bettors lose over time

If you or someone you know struggles with problem gambling, free resources are available. The National Council on Problem Gambling provides a confidential helpline at 1-800-522-4700.

The examples in this guide are illustrative only and do not constitute betting advice or recommendations. Sports betting is legal for adults 21+ in states where regulated. Availability varies by state and sportsbook.