No vig.
No mystery.
Remove the proportional margin from a two-outcome market. See raw implied chance, fair probabilities and fair odds. These are market-derived estimates—not true probabilities.
Updated Nov 2026 · checked Nov 10 ET$4.99 first month, then $9.99/month. Cancel anytime. Applicable tax may be added.
Full Access at Whop ↗Enter both sides of the same market.
Raw implied 52.38%
Fair decimal 2.0000
Fair American +100.00
Raw implied 52.38%
Fair decimal 2.0000
Fair American +100.00
Implied total: 104.76% · overround: 4.76%
Overround: implied total exceeds 100%.
Every input has a job.
Use two mutually exclusive, exhaustive outcomes with the same settlement rules. An over and under must share the same line. For markets with a push, this is conditional on no push; it does not estimate the push probability. Do not feed unrelated legs, different thresholds or different games into this calculation.
Negative American: |odds| ÷ (|odds| + 100)
Decimal: 1 ÷ odds
Overround = implied A + implied B − 1
Overround is not a measured sportsbook profit margin. Different de-vig models can allocate the margin differently, especially with asymmetric prices. Compare proportional estimates with an independent probability model rather than treating them as certainty.
| Known input | Expected result |
|---|---|
| −110 / −110 | 52.380952% implied each; 4.761905% overround; fair 50% / 50%; decimal 2.00 |
| +150 / −170 | 40% and 62.962963% implied; fair 38.848921% / 61.151079% |
| 2.10 / 2.10 | 47.619048% implied each; −4.761905% underround; fair 50% / 50% |
| Invalid / missing input | Show a clear error and hide stale results; no Infinity or NaN. |
Practical questions.
Does “no-vig” mean this is the true chance?
No. It is the chosen normalization of a market price. The market and model can both be wrong.
Does an underround prove an available arbitrage?
No. Available stakes, timing, limits, fees, cancellation and settlement rules still matter.
Are fees included?
No. This is a sportsbook odds normalization, not a fee-adjusted prediction-contract calculator. Use the Kalshi page’s separate quoted-fee worksheet.
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