No-Vig Odds Calculator

This removes the bookmaker margin from a priced market and returns the fair probability and fair odds for every outcome. Enter each price in American or decimal odds, from a two-way line up to an eight-runner field, and it reports the total implied probability, the overround, the margin as a share of a balanced book, and the de-vigged price for each outcome. Three published methods are offered, because they disagree: the multiplicative one scales every price by the same factor, the additive one takes the same number of percentage points off each, and the power one raises each to the exponent that makes them sum to one. The three agree closely on a balanced two-way line and pull apart on long prices, so the first outcome is always shown under all three.