No-vig calculator
Enter both sides of a market from one sportsbook. See how much the book keeps, and the fair probability and fair price of each side once that margin is removed.
- Vig
- 3.48%Implied total 103.48%. The amount over 100% is the book's margin on this market, also called the overround or juice.
- Hold
- 3.36%The share of balanced handle the book keeps: 1 minus 1 over the implied total.
Fair odds with the vig removed
Side 1 priced at -150
- Fair odds
- -140
- 1.71 in decimal odds
- Fair chance
- 58.4%
- Priced as 60.0%; the gap is the margin on this side.
Side 2 priced at +130
- Fair odds
- +140
- 2.40 in decimal odds
- Fair chance
- 41.6%
- Priced as 43.5%; the gap is the margin on this side.
What the vig is
A sportsbook prices both sides so their implied probabilities add up to more than 100%. A standard -110 / -110 line implies 52.38% on each side, 104.76% in total. The extra 4.76 points is the overround. The hold, what the book keeps from money bet evenly on both sides, is 1 − 1 / 1.0476 = 4.55%, the figure this calculator and the hold calculator show.
How the fair price is found
The calculator raises each side's implied probability to the same power, the one that makes them add up to exactly 100%. That is the power method. For -150 / +130: implied 60.00% and 43.48%, total 103.48%; the power that brings them to 100% is 1.053, which gives fair chances of 58.40% and 41.60%. The fair prices are about -140 and +140.
Books load more of their margin onto the longshot than the favourite, and the power method takes it back off where it sits. The simpler multiplicative method, dividing each side by the total, shrinks both by the same proportion (57.98% and 42.02% here) and so leaves the longshot too much. On a close two-way market the two land within a few cents; on a big favourite they part: a 1.08 / 8.53 line gives the underdog 11.2% multiplicative and 8.5% power. Either way the fair price is an estimate.
Why it matters
A fair price from a sharp book is a yardstick. When another book offers a longer price than the fair one, the bet has positive expected value. ArbWins's +EV board does exactly this: it de-vigs Pinnacle's line on every market and compares every other book against it, every 20 seconds.