Legal, state, or operator approval question
This tool does not verify legality, state approval, operator status, or license claims.
Use state guides
Last updated May 15, 2026
|
Formula reviewed May 15, 2026
Odds Converter
Convert American, decimal, and fractional odds, see raw implied probability, and run a cautious market margin/no-vig check. The tool explains price meaning; it does not identify value bets, verify legality, or tell you to stake.
Owner intent: this page converts quoted odds and explains the market math behind raw implied probability and no-vig normalization.
It does not compare sportsbooks, recommend bets, calculate expected value, choose stakes, verify state eligibility, handle taxes, or resolve ticket disputes.
Disclosure
This page is an educational converter. If commercial links appear elsewhere on the site, they do not change the formulas, labels, validation rules, or limitations shown here.
Privacy and data handling
The live converter runs in your browser. Do not enter account IDs, ticket numbers, Social Security numbers, payment details, login credentials, or private screenshots. The visible formulas below remain usable without JavaScript.
Responsible-play boundary
If converting odds creates urgency, chasing, repeated deposits, or pressure to raise stakes, stop before using another tool. For confidential U.S. support, call or text 1-800-MY-RESET. State-specific resources may vary.
Choose the right odds task
Pick the wording that matches what you have. This keeps the tool inside its job instead of turning odds conversion into betting advice.
Convert odds
This output is the implied probability of the quoted price. It is not a no-vig fair probability.
Market margin and no-vig check
Use this only when you have the full market, such as both sides of a spread/total or all three outcomes in a 3-way market. Positive American odds should include a plus sign, such as +150.
Need a dedicated full-market workflow? Use the no-vig / overround calculator for two-way, three-way and N-way market normalization.
Probability to odds
Use this when you already have a probability estimate and only need the equivalent odds display. This does not decide whether your probability is accurate.
Stake and payout math
Estimate profit and total return for a stake and quoted odds. This is payout math only; it is not expected profit, bankroll advice, or a recommendation to place a wager.
Valid input rules
American
Enter a non-zero quoted price such as +150 or -110. Zero is not a valid American-odds quote.
Decimal
Decimal odds must be strictly greater than 1.00 because 1.00 implies no return above stake and breaks normal odds conversion.
Fractional
Use a positive numerator and denominator, such as 3/2 or 10/11. Zero and negative values are not valid fractional quotes.
Formula and rounding policy
American to decimal: positive American odds convert as (American / 100) + 1; negative American odds convert as (100 / absolute American) + 1.
Fractional to decimal: add 1 to the profit ratio, so 3/2 becomes 2.50.
Raw implied probability: 1 / decimal x 100%. This is the probability implied by the quoted price, not a no-vig fair probability.
Market total: add raw implied probabilities for every outcome in the market. A total above 100% is the quoted overround.
No-vig normalization: divide each outcome's raw implied probability by the market total. This removes quoted margin from the input market, but it is not a prediction model.
Probability to decimal odds: 100 / probability percentage. Convert the decimal result to American and fractional display as a format conversion only.
Payout math: profit equals stake x fractional profit ratio; total return equals stake + profit. This is not expected profit.
Rounding policy: books often round displayed decimals and American prices. When the source quote is rounded, the converted output may normalize to a nearby fractional display such as 91/100 instead of 10/11.
If the original source quote is American -110, this converter preserves the exact fractional ratio 10/11. If the source quote is a rounded decimal like 1.91, the normalized fractional display reflects that rounded input.
Formula registry
| Registry item | Current setting | User-facing boundary |
|---|---|---|
| Model version | Odds Conversion Model v2.1, reviewed May 15, 2026 | Educational conversion and market normalization only. |
| Inputs | American, decimal, fractional odds; optional second, third, and additional full-field market outcomes; probability percentage; stake amount. | Positive American prices should include a plus sign in the market checker. |
| Outputs | Converted odds, raw implied probability, market total, overround, no-vig probabilities and odds, reverse probability odds, payout profit, and total return. | No output is a betting recommendation, fair-price certification, or legal availability check. |
| Known exclusions | Expected value, bankroll sizing, line shopping, true-probability modeling, state eligibility, settlement disputes, taxes, and operator approval. | Use the correct next route when the question is no longer odds conversion. |
Raw implied probability is not fair probability
What the converter shows
Raw implied probability is the chance implied by the quoted price itself. It answers "what probability is this line pricing?"
What the converter does not show
It does not remove vig, identify the fair price, or prove that a bet has value. You still need the full market or a separate fair-price model for that.
Vig, hold, overround and no-vig terms
Sportsbooks and calculators use these terms differently. This page keeps the definitions narrow so the output does not become a betting model.
| Term | Meaning | This tool does |
|---|---|---|
| Raw implied probability | Probability from a quoted price. | Yes, for American, decimal and fractional odds. |
| Overround | Market total above 100% after adding raw implied probabilities. | Yes, when the full market is entered. |
| Vig / juice | Common shorthand for bookmaker margin in pricing. | Approximate through market total; it does not audit a sportsbook. |
| Hold | Operator margin expression often used in reporting or market context. | Explain only; it does not calculate operator hold from real handle/revenue data. |
| No-vig probability | Raw market probabilities normalized to total 100%. | Yes, as mathematical normalization, not prediction. |
| True probability | Your model or evidence-based estimate of what should happen. | No. Use separate modeling and risk controls. |
Why both sides can add to more than 100%
Example: -110 on Team A and -110 on Team B each imply 52.38% from the quoted price.
Add them together and the market totals 104.76%. That extra 4.76% is the bookmaker margin. A single converted line can show the quoted probability, but it cannot tell you the no-vig fair chance by itself.
When conversion is not enough
You need fair probability
If the next question is whether a line is actually good value, conversion alone is not enough. You need the full market or your own probability model.
You need a betting decision
If the next question is stake size, bankroll discipline, or parlay payout, move to the tool that owns that job instead of stretching the converter past its scope.
Odds conversion does not answer state eligibility
Converting a line does not prove that the sportsbook, market, event, location, or account route is available or approved in a state. If the question is location, operator source, tax records, or complaint path, move to the state or sportsbook banking route before using more tools.
Worked examples
+150 quote
+150 converts to 2.50 decimal, 3/2 fractional, and 40.00% raw implied probability.
-110 quote
-110 converts to 1.91 decimal, 10/11 fractional, and 52.38% raw implied probability. That is the bookmaker-implied price, not a fair 52.38% no-vig chance.
5/1 quote
5/1 converts to 6.00 decimal, +500 American, and 16.67% raw implied probability.
Common odds conversion table
This crawlable table covers common prices from -1000 to +1000. Values are rounded for display, so always use the live converter for the exact quote shown on a ticket or market screen.
| American | Decimal | Fractional | Raw implied probability |
|---|---|---|---|
| -1000 | 1.10 | 1/10 | 90.91% |
| -900 | 1.11 | 1/9 | 90.00% |
| -800 | 1.13 | 1/8 | 88.89% |
| -700 | 1.14 | 1/7 | 87.50% |
| -600 | 1.17 | 1/6 | 85.71% |
| -500 | 1.20 | 1/5 | 83.33% |
| -400 | 1.25 | 1/4 | 80.00% |
| -300 | 1.33 | 1/3 | 75.00% |
| -250 | 1.40 | 2/5 | 71.43% |
| -200 | 1.50 | 1/2 | 66.67% |
| -150 | 1.67 | 2/3 | 60.00% |
| -125 | 1.80 | 4/5 | 55.56% |
| -110 | 1.91 | 10/11 | 52.38% |
| -100 | 2.00 | 1/1 | 50.00% |
| +100 | 2.00 | 1/1 | 50.00% |
| +110 | 2.10 | 11/10 | 47.62% |
| +125 | 2.25 | 5/4 | 44.44% |
| +150 | 2.50 | 3/2 | 40.00% |
| +200 | 3.00 | 2/1 | 33.33% |
| +250 | 3.50 | 5/2 | 28.57% |
| +300 | 4.00 | 3/1 | 25.00% |
| +400 | 5.00 | 4/1 | 20.00% |
| +500 | 6.00 | 5/1 | 16.67% |
| +600 | 7.00 | 6/1 | 14.29% |
| +700 | 8.00 | 7/1 | 12.50% |
| +800 | 9.00 | 8/1 | 11.11% |
| +900 | 10.00 | 9/1 | 10.00% |
| +1000 | 11.00 | 10/1 | 9.09% |
Where this converter can mislead you
Raw implied is not fair probability
A single converted line does not remove vig. A quoted implied probability still includes bookmaker margin. Use the market checker only when you have the full market.
-110 is not a fair 52.38 percent chance
It is the implied probability of the quoted price. A fair no-vig estimate requires the full market, not a single converted line.
Rounded displays can differ
A book that shows 1.91 may be representing a price that originates as -110. Small rounding differences can change the normalized fractional output.
Conversion is not line shopping
Converting a quote does not tell you whether another book has a better line, whether the event is legal to bet in your state, or whether the wager is positive EV.
What to save when an odds conversion becomes a ticket dispute
This is a record checklist, not legal advice and not a dispute decision. Do not enter private account numbers, document IDs, payment details, or screenshots into this page.
- Original odds format and source screen before submission.
- Accepted ticket with odds, stake, event, market, and timestamp.
- Any odds-change, rejected-bet, void, cash-out, or settlement message.
- Market rules if the issue involves push, void, stat correction, or settlement.
- Support transcript if the displayed odds and accepted odds differ.
Ticket evidence packet builder
When this tool stops being the right owner
Account, payout, or document issue
Move to banking, withdrawal, or scam routes when support, KYC, payment, or account records decide the outcome.
Withdrawal verificationControl, chasing, or harm issue
Use responsible gambling support before opening another calculator or gambling page.
Responsible gambling basicsUse the next tool only after price meaning is clear
Parlay payout math
Use the parlay calculator only after quoted prices are normalized. It estimates payout math; it does not recommend a parlay.
Kelly stake sizing
Use Kelly only when you have a credible win-probability estimate beyond raw quoted probability.
Read the glossary
Use the glossary when you need betting terms explained rather than converted.
Deep odds literacy paths
Betting Terms
Use for market and settlement vocabulary.
Parlay Guide
Use when multiple legs change failure risk.
No-Vig / Overround Calculator
Use when you have the full market and need normalized probabilities, not picks.
Kelly Tool
Use only with credible probability estimates beyond raw quoted odds.
Bankroll Planner
Use to set exposure boundaries before staking.
Sportsbook Limits
Use when stakes, max payout, or rejected tickets are the issue.
Sportsbook Verification
Use when accepted odds or ticket records need preservation.
Public QA test matrix
These cases define the visible acceptance checks for this tool version. They are not betting advice or sportsbook validation.
| Case | Input | Expected output | Status |
|---|---|---|---|
| Positive American | +150 | 2.50 decimal, 3/2 fractional, 40.00% raw implied. | Passed |
| Negative American | -110 | 1.91 decimal, 10/11 fractional, 52.38% raw implied. | Passed |
| Decimal validation | 1.00, 0, negative, or text | Blocked with validation message. | Passed |
| Two-way margin | -110 / -110 | 104.76% market total, 4.76% overround, 50.00% / 50.00% no-vig. | Passed |
| Three-way market | +150 / +220 / +240 | Three normalized no-vig probabilities that total 100%. | Passed |
| N-way visible market | A, B, draw, plus additional full-field outcomes | Every entered outcome appears in the normalized table with raw implied, no-vig probability, and no-vig odds. | Passed |
| No-vig odds output | -110 / -110 | Each side shows 50.00% and +100 / 2.00 / 1/1 no-vig odds. | Passed |
| Probability reverse conversion | 40% | +150 American, 2.50 decimal, 3/2 fractional. | Passed |
| Payout math | $25 stake at +150 | $37.50 profit and $62.50 total return; labeled as payout math only. | Passed |
| Share URL | Convert +150 or run market checker | Share URL stores assumptions only and keeps canonical at /tools/odds/. | Passed |
| Copy/export controls | Copy summary, download TXT/CSV, or print | Local summary/export contains assumptions and outputs only, with private-data warning. | Passed |
| Owner stop | Question asks what to bet or whether the sportsbook is legal | Route away from converter to state, bankroll, Kelly, or support pages. | Passed |
{"case":"two_way_minus_110","inputs":["-110","-110"],"expected":{"marketTotal":"104.76%","overround":"4.76%","noVig":["50.00%","50.00%"]}}
Source and evidence register
| Source row | Evidence type | Used for | Review cadence |
|---|---|---|---|
| Internal formula registry, Odds Conversion Model v2.1 | VERIFIED internal model | Conversion formulas, rounding policy, market total, N-way no-vig normalization, copy/export output. | Quarterly or when tool logic changes. |
| Visible tool QA matrix | VERIFIED public test cases | Acceptance tests for supported inputs, invalid inputs, and market checker output. | Before publish and after each formula update. |
| NCPG help resources | VERIFIED help routing | Responsible-play call/text wording and support routes. | Quarterly and after public helpline wording changes. |
| Sportsbook price, market, or ticket display | EVIDENCE REQUIRED BEFORE EXACT CLAIM | Any claim about a real market, settlement, availability, line movement, or accepted ticket. | Exact page/user context only; not inferred from this converter. |
Changelog
May 15, 2026: upgraded to Odds Conversion Model v2.1; added market margin checker, no-vig probability normalization, no-vig odds output, probability-to-odds reverse converter, payout math module, scenario presets, shareable result URLs, copy/export controls, common odds table, vig/hold terminology table, ticket evidence packet builder, QA matrix, fixture, source register, responsible-play boundary, privacy note, and no-News navigation.
Apr 23, 2026: earlier odds-format converter with American, decimal, fractional, and raw implied probability output only.
Odds converter FAQ
Does raw implied probability show the fair probability?
No. Raw implied probability is calculated from the quoted price and can include bookmaker margin. A no-vig estimate requires the full market and is still not a prediction.
What is vig or overround?
Vig or overround is the amount by which the raw implied probabilities in a market total above 100 percent. It is a margin signal, not a recommendation.
Can the no-vig checker tell me what to bet?
No. It only normalizes quoted market probabilities. It does not provide a betting model, bankroll advice, legal eligibility, or a recommendation to stake.
Can I use the no-vig checker for a three-way market?
Yes, if you have all outcomes from the same market, such as home, draw, and away. For futures or larger fields, enter every visible outcome before treating the normalized table as complete.
What is the difference between no-vig probability and true probability?
No-vig probability normalizes the prices in a market to remove quoted margin. True probability is a separate model or evidence-based estimate and is not produced by this converter.
Why do two -110 sides add above 100 percent?
Each -110 side implies about 52.38 percent from the quoted price, so both sides total about 104.76 percent. The extra amount is the market margin.
Can odds conversion verify state or operator eligibility?
No. Odds conversion does not verify sportsbook legality, state availability, account status, payment approval, taxes, or settlement rules.
Maintained and reviewed by
Model maintenance owner: the Playbook USA Tools Team. Written by Michael Johnson, edited by Sarah Roberts, and responsible-gambling language reviewed by David Thompson.
Review scope: formula accuracy, rounding policy, input validation, no-vig labeling, privacy language, and owner-intent boundaries.
Last updated: May 15, 2026. Formula reviewed: May 15, 2026. Current scope: American, Decimal, Fractional, raw implied probability, market total, overround, no-vig normalization, reverse probability conversion, payout math, share URLs, and common odds table. This page is informational only and is not betting, financial, legal, or tax advice.
Responsible gambling help
For national help in the U.S., call or text the National Problem Gambling Helpline at 1-800-MY-RESET, or use online chat through the National Council on Problem Gambling. Existing access points may remain active, and state-specific resources may vary.
Help routing checked: May 15, 2026. Re-check NCPG phone, text, and chat wording before each quarterly tools update.