Vig & No-Vig Calculator

The vig calculator strips the house margin out of quoted market prices and shows you the true implied probability for each outcome. In any prediction market or sportsbook, the sum of all outcome prices exceeds $1.00 — that excess is the overround, also called vig or juice. It's the platform's built-in edge. When you trade at quoted prices without adjusting for vig, you're implicitly paying that margin on every position.

Enter the prices for each side of a market and the calculator computes the total overround, the vig percentage, and the no-vig fair probability for each outcome. For a two-outcome market priced at 0.55 and 0.52, the total is 1.07 — meaning the market contains 7% vig. The no-vig probability for each side is its price divided by the total, giving you the market's true estimate stripped of that margin.

This matters most when you're trying to assess whether your own probability estimate represents an edge over the market. If you think an event has a 60% chance and the no-vig price is 58%, you have a potential 2-point edge. But if you're comparing against the raw quoted price rather than the no-vig price, you might conclude you have a larger edge than actually exists. The no-vig price is the honest baseline for edge calculation.

Use this alongside the Expected Value calculator to measure your true edge, and the Market Fees calculator to factor in platform costs. All three together give you a complete picture of whether a trade is worth making.