Vig Calculator — Sportsbook Juice & True Odds Finder

Using the vig calculator is simple. Enter the American odds for both sides of a bet — for example, -110 / -110 on a standard NFL point spread, or -115 / -105 on a moneyline with shaded lines. The calculator will instantly show you the vig percentage, the implied probabilities with the juice baked in, and the true (no-vig) fair odds that reflect the actual probability of each outcome.

American odds can be entered as negative numbers (favorites, e.g. -110) or positive numbers (underdogs, e.g. +130). The calculator supports all standard American odds formats used by US sportsbooks.

Use the no-vig odds to compare lines across books — if one book offers better odds than the fair value, you have a positive expected value (+EV) opportunity.

The vig calculation follows these steps:

1. Convert American odds to implied probability:
   • Negative odds (e.g. -110): prob = |odds| ÷ (|odds| + 100)
   • Positive odds (e.g. +130): prob = 100 ÷ (odds + 100)
2. Overround = Implied Prob A + Implied Prob B
   (Always > 100% when vig is present; e.g. -110/-110 gives 104.76%)
3. Vig % = (Overround − 1) ÷ Overround × 100
4. No-vig probability = Implied Prob ÷ Overround
5. No-vig American odds = convert fair probability back to American format

For standard -110 / -110 lines: each side has an implied probability of 52.38%, giving an overround of 104.76% and a vig of 4.55%. The true fair odds for both sides are -100 (even money), meaning a coin-flip event.

Example 1 — Standard Point Spread (-110 / -110)

• Side A: -110 → implied probability 52.38%
• Side B: -110 → implied probability 52.38%
• Overround: 104.76%
• Vig: 4.55%
• No-vig odds: -100 / -100 (true 50/50 coin flip)

For every $110 bet on each side, the book collects $220 and pays out $210. The $10 difference is the house profit — 4.55% of total handle.

Example 2 — Moneyline with Juice (-150 / +130)

• Side A (favorite): -150 → implied probability 60.00%
• Side B (underdog): +130 → implied probability 43.48%
• Overround: 103.48%
• Vig: 3.36%
• No-vig odds: Side A ≈ -138, Side B ≈ +138

The book shades the line by about 6 cents total. If you can find a book offering +135 on the underdog, that is a +EV bet relative to the true fair odds.

Why Vig Matters for Bettors

At -110 on both sides you need to win 52.38% of your bets just to break even. At -115, the break-even rate climbs to 53.49%. Shopping for the best lines — even saving half a point — materially improves your long-run results. Line shopping across multiple books is the single highest-ROI habit for serious sports bettors.