Devig Calculator (Fair & No-Vig Odds)

What is vig, and why devig?

Vig (short for vigorish, also called juice or the overround) is the margin a sportsbook bakes into its prices. A coin flip should be priced at +100 on both sides — but a sportsbook will price it -110 / -110 instead. The gap between the implied probabilities of the two sides and 100% is the vig. That extra 4.5% or so is what the book takes home as its margin over a large number of bets.

Devigging is the process of mathematically removing that margin to estimate the book's true opinion of each side's probability. Once you have fair no-vig odds, you can compare them to the actual odds at another book: if the other book is pricing a side better than the fair no-vig price, that bet has positive expected value.

Devig, true odds, no-vig, fair odds — same thing

These terms get used interchangeably and all describe the same output of this calculator. True odds (or fair odds) are the prices a sportsbook would offer if it charged no margin — the prices that reflect each outcome's actual probability. No-vig odds name the same number by how it's produced: strip the vig out and what remains is the fair, true price. So a "true odds calculator", a "no-vig calculator", and a "devig calculator" are the same tool — this one.

Most conservative, multiplicative, additive, and power

Three underlying methods are commonly used. Multiplicative divides each implied probability by the total — simple and widely used. Additive subtracts an equal portion of the vig from each side, which can slightly skew results on asymmetric markets. Power finds an exponent that makes the implied probabilities sum to 1 — better for long-priced markets (big favorites / big underdogs) because it preserves log-odds ratios.

The default, Most conservative, runs all three methods and picks whichever gives the smallest implied edge — the lowest fair probability for side 1. That's the safest interpretation: you won't overestimate your edge. This is the same approach DawBets uses.

A worked example

A two-way market priced at -110 / -110 has implied probabilities of 52.38% on each side. Together they sum to 104.76% — the extra 4.76% is the vig. Devigging multiplicatively (dividing each by 1.0476) gives 50.00% / 50.00%, which is +100 / +100 in American odds. That's the fair, true price; anything worse means you're paying margin to the book.

Using fair odds to spot +EV bets

Devigging is most useful when comparing two sportsbooks. Devig a sharp book's market (like Pinnacle or Circa) to get a fair price estimate, then check another book's price for the same market. If the other book is offering a better price than the fair estimate, you've found a +EV bet. This is the foundation of value betting and is how every +EV finder (including DawBets) works under the hood.

When to use this calculator

Use the devig calculator any time you want to know the real no-vig probability behind a sportsbook's prices. Typical workflow: open a sharp book like Pinnacle, copy the two-way prices from a moneyline or total, paste them in here, and read the fair no-vig odds. Then check the same market at a retail book (DraftKings, FanDuel, BetMGM) — if their price is better than the fair no-vig price, that's a +EV bet.

Want just the margin, not the fair odds? Use the vig calculator. Need to convert a single price to a percentage? Try the implied probability calculator. For real-time +EV discovery across 20+ sportsbooks without manual devigging on every market, the DawBets +EV feed does the line shopping for you.

Frequently asked questions