Odds math tool - reviewed May 15, 2026
No-Vig / Overround Calculator
Enter every outcome in a full market to estimate market total, overround and no-vig probabilities. This page normalizes quoted prices; it does not identify picks, prove edge, predict outcomes or verify sportsbook legality.
Owner intent: this tool owns full-market vig removal math. For one-line format conversion use the odds converter. For stake sizing use the Kelly calculator only if you already have a credible independent probability estimate.
21+ only. No-vig math is not a reason to bet, chase losses, raise stake size or treat sportsbook prices as truth. If the result creates urgency or loss-recovery pressure, stop and call or text 1-800-MY-RESET for confidential support. State-specific resources may vary.
Privacy: calculations run in your browser. Do not enter account IDs, ticket numbers, payment details, identity documents, addresses or private sportsbook messages. Copy/export controls save only the assumptions visible on this page.
Use this for
Two-way spreads/totals, three-way markets and full-field markets where every outcome is entered.
Do not use this for
A single line, incomplete market, live odds screenshot, legal verification, account disputes or betting recommendations.
Output meaning
No-vig probability is normalized quoted market math. It is not true probability, edge or expected profit.
No-vig market calculator
Enter one price per line. Supported formats: American (-110, +150), decimal (1.91) and fractional (3/2).
Result
Enter a full market and calculate. A single converted line does not remove vig.
| Outcome | Quoted odds | Raw implied probability | No-vig probability | No-vig American | No-vig decimal | No-vig fractional |
|---|---|---|---|---|---|---|
| - | - | - | - | - | - | - |
Formula and no-JS fallback
Visible formula
- American positive raw probability:
100 / (odds + 100). - American negative raw probability:
abs(odds) / (abs(odds) + 100). - Decimal raw probability:
1 / decimal. - Market total:
sum(raw probabilities). - Overround:
market total - 100%. - No-vig probability:
raw probability / market total.
Worked example
For -110 / -110, each side has raw implied probability of about 52.38%. Market total is 104.76%, overround is 4.76%, and each no-vig probability normalizes to 50.00%.
Without JavaScript, use the formulas above and verify every outcome in the market before normalizing.
Raw implied, overround, vig and true probability
| Term | Meaning | What this page does |
|---|---|---|
| Raw implied probability | Probability implied by one quoted price before margin removal. | Calculates it for each entered price. |
| Overround | Amount by which the full market total exceeds 100%. | Shows it when the full market is entered. |
| No-vig probability | Raw probabilities normalized so the full market totals 100%. | Calculates it, but does not call it true probability. |
| True probability | A separate user/model estimate of outcome likelihood. | Does not estimate it. |
| Hold / juice / vig | Common terms for sportsbook margin, expressed in different contexts. | Approximates margin through market total only. |
When the calculator should not be used
Incomplete market
If you only have one side or some outcomes are missing, use the parent odds converter for format conversion only.
Live or moving price
If the prices changed before you entered all outcomes, the market total may no longer describe a real quoted market.
Decision pressure
If the output makes you feel rushed, stop. No-vig math is not a signal to chase or raise stakes.
QA and public test fixture
| Case | Input | Expected output | Status |
|---|---|---|---|
| Two-way standard | -110 / -110 |
104.76% market total, 4.76% overround, 50.00% / 50.00% no-vig. | Passed |
| Three-way market | +150 / +220 / +240 |
Three normalized probabilities totaling 100%. | Passed |
| Decimal input | 1.91 / 1.91 |
Valid raw and no-vig outputs. | Passed |
| Invalid American zero | 0 |
Input rejected. | Passed |
| Incomplete market | One valid price only | Warn user that no-vig requires at least two outcomes. | Passed |
Machine-readable fixture
{"case":"two_way_minus_110","inputs":["-110","-110"],"expected":{"marketTotal":"104.76%","overround":"4.76%","noVig":["50.00%","50.00%"]}}Source register
| Source / method | Used for | Status | Last checked |
|---|---|---|---|
| Internal Odds Conversion Model v1.0 | American, decimal, fractional, raw implied, market total and no-vig normalization formulas. | VERIFIED INTERNAL METHOD | May 15, 2026 |
| The Playbook USA Tools QA log | Input validation, no-vig examples, export controls and visible formula parity. | VERIFIED INTERNAL QA | May 15, 2026 |
| NCPG helpline wording | Responsible-play routing and support language. | VERIFIED SUPPORT ROUTE | May 15, 2026 |
FAQ
What does no-vig mean?
No-vig means the quoted market probabilities are normalized so the market total equals 100%. It is not a prediction.
Can one odds line remove vig?
No. A single line can be converted into raw implied probability, but removing vig requires the full market.
Is no-vig probability the same as true probability?
No. True probability requires a separate model and can still be wrong.
Can this handle three-way markets?
Yes, if every outcome is entered. Missing draw or field outcomes invalidate no-vig output.
Next pages by odds problem
Odds Converter
Use for one-line American, decimal, fractional and payout math.
Kelly Calculator
Use only after you have a credible independent probability estimate.
Bankroll Planner
Use to set exposure boundaries before any stake decision.
Parlay Calculator
Use for payout math only, not as a parlay recommendation.
Betting Terms
Use when market, odds, settlement or vig language is unclear.
Responsible Gambling
Use if odds math creates urgency, chasing or pressure to raise stakes.
Changelog
May 15, 2026: published No-Vig / Overround Calculator v1.0 with two-way, three-way and N-way market support, no-vig probability and odds output, copy/export controls, QA matrix, formula registry, source register, FAQ schema, privacy note, responsible-play boundary and no-News navigation.