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Vig Calculator: Calculate the House Edge on Any Market

Last Updated: March 4, 2026

Vig — the margin sportsbooks build into every line — is the single largest cost bettors face over time. Enter odds from both sides of any market into the calculator above, and it returns the vig percentage, the overround, and the no-vig implied probabilities that reveal the book’s true opinion.

How Do You Use the Vig Calculator?

Enter the odds for both sides of a two-outcome market. The calculator accepts American, decimal, and fractional formats. It outputs:

  1. Each side’s implied probability — The raw probability embedded in the odds before vig removal
  2. Total implied probability (overround) — The sum of both sides. Anything above 100% is the book’s margin
  3. Vig / hold percentage — The effective commission extracted from both sides combined
  4. No-vig implied probabilities — The true probabilities after removing the book’s margin proportionally

These no-vig numbers are critical for identifying value. If you estimate a side’s true probability at 58% and the no-vig line prices it at 52%, you have a 6-point edge. If the no-vig price is already 58%, there is no edge regardless of how the raw odds look. For a full breakdown of this concept, see our guide on what vig is and how sportsbooks use it.

How Does the Vig Calculation Work?

The math is straightforward. Convert both sides to implied probability, sum them, and measure the excess above 100%.

LineSide ASide BOverroundVig (Hold)
-110 / -11052.38%52.38%4.76%4.55%
-115 / +10053.49%50.00%3.49%3.37%
-150 / +13060.00%43.48%3.48%3.36%
-200 / +17066.67%37.04%3.71%3.57%
-300 / +24075.00%29.41%4.41%4.22%

Notice that vig is not constant. Lopsided lines (-200/+170) can carry more or less vig than the standard -110/-110 depending on how each book prices the spread. The calculator reveals this instantly, while mental math gets unreliable on non-standard lines.

Why Does Vig Matter for Your Betting Results?

Vig is the headwind every bettor faces. A 52.4% win rate breaks even at -110 juice. Every percentage point of additional vig raises that break-even threshold.

At volume, the differences compound. A bettor placing 500 wagers per year at $100 average stake:

  • At 4.5% vig: $2,250 paid in margin annually
  • At 6.0% vig: $3,000 paid in margin annually
  • At 3.0% vig: $1,500 paid in margin annually

That $1,500 difference between a high-vig book and a low-vig book is pure profit retained. Shopping lines across multiple sportsbooks compresses effective vig by 1-2 percentage points per wager. Use the odds converter to compare pricing across formats, and check the Odds Reference dashboard for real-time line comparisons.

How Does Vig Compare to Prediction Market Fees?

Prediction markets do not embed vig the same way sportsbooks do. On platforms like Polymarket and Kalshi, prices are set by traders in an order book, not imposed by a bookmaker. The overround in the order book reflects natural bid-ask spread rather than a mandated margin.

Instead, prediction market platforms charge explicit fees. Kalshi takes 7% of net winnings. Polymarket’s CLOB spread functions as an implicit 1-3% cost. These fees are more transparent than sportsbook vig, but they still reduce your net return.

The vig calculator helps bridge this comparison. Enter both sides of a prediction market event (YES price and NO price from the same platform) to see the effective spread. If YES trades at $0.52 and NO at $0.51, the combined cost of $1.03 implies a 3% overround — comparable to a tight sportsbook line.

Understanding your true cost per wager — whether that is sportsbook vig or platform fees — is foundational to calculating implied probability and identifying positive expected value.

Key Takeaways

  • Vig is the overround above 100% when you sum both sides’ implied probabilities — the calculator computes this instantly for any odds format
  • No-vig implied probabilities reveal the book’s true opinion, stripping away the margin and exposing where value exists
  • The difference between a 3% vig book and a 6% vig book costs a 500-bet-per-year bettor $1,500 annually
  • Prediction markets replace traditional vig with explicit fees, but the calculator still measures the effective spread on any two-sided market
  • Line shopping remains the simplest way to reduce effective vig — compare odds across books before placing any wager

Frequently Asked Questions

How do you calculate vig on a bet?
Convert both sides of a line to implied probabilities, sum them, and subtract 100%. The excess is the overround. The hold percentage (vig) is the overround divided by 1 plus the overround. For example, -110/-110 implies 52.38% on each side, totaling 104.76%. The vig is 4.76/104.76 = 4.55%. The calculator above handles this automatically for any odds format.
What is a typical vig on NFL bets?
Standard NFL point spreads carry 4-5% vig, with -110 on both sides as the industry baseline. Player props run 8-15%, same-game parlays 15-30%, and futures 10-25%. Line shopping across multiple books can reduce your effective vig by 1-2 percentage points per wager, which compounds significantly over hundreds of bets.
Do prediction markets have vig?
Prediction markets do not embed traditional vig into contract prices because odds are set by traders, not a bookmaker. Instead, platforms charge explicit fees: Kalshi takes 7% of net winnings, while Polymarket's CLOB spread runs roughly 1-3%. These fee structures are more transparent than sportsbook vig but still represent a real cost to the bettor.
What are no-vig implied probabilities?
No-vig probabilities are the true implied probabilities after removing the sportsbook's margin. For a -150/+130 line, the raw implied probabilities are 60% and 43.5%, totaling 103.5%. Removing the 3.5% overround proportionally gives no-vig probabilities of roughly 58% and 42%. These represent the book's actual opinion of each side's chances.