What Is the Vig — and How to Beat It (Devigging)

By Cobia Picks · Updated July 3, 2026 · ~6 min read

Every price you see at a sportsbook has a tax baked into it, and most bettors never notice they're paying it. That tax is the vig — the reason a coin-flip bet doesn't pay you even money. If you want to know whether a bet is actually good, you first have to strip the vig out and find the market's true price. That process is called devigging, and it's one of the most useful skills a bettor can learn.

What the vig actually is

The vig — also called the juice, the hold, or the margin — is the commission a sportsbook builds into its odds. It's how the house makes money regardless of who wins. Instead of charging a fee up front, the book shades every price slightly in its own favor, so the two (or more) sides of a market add up to more than 100% probability.

The classic example is the standard -110 / -110 line you see on point spreads and totals. On a truly 50/50 event, a fair book would pay you +100 (even money) on each side. Instead it pays -110: you must risk $110 to win $100. That extra $10 you're laying is the vig.

Why -110/-110 is a ~4.5% hold

Turn each price into its implied probability — the win rate you'd need just to break even at those odds. For American odds of -110, the formula is 110 ÷ (110 + 100) = 0.5238, or 52.38%.

Now add up both sides of the market:

Side A at -110 → 52.38%
Side B at -110 → 52.38%
Total → 104.76%

A fair market's probabilities sum to exactly 100%. This one sums to 104.76%. That extra ~4.76% is the overround — the book's built-in edge. The actual hold (the share of total money wagered the book expects to keep) works out to about 4.5% on a balanced -110/-110 market. That's the toll you pay on every standard bet, and it's exactly why long-run winners need a real edge, not just a hunch.

The break-even truth

Because -110 implies 52.38%, you must win 52.38% of your -110 bets just to break even. Hit 50% — a genuine coin flip — and you slowly go broke. The gap between 50% and 52.38% is the vig quietly draining your bankroll. Beating the vig is the entire game.

How to devig a line

Devigging means removing that overround to recover the market's honest, no-vig probability. The most common method — the "multiplicative" or normalization method — is simple: divide each side's implied probability by the total.

Worked example: a two-way market

Say a book prices a game -150 / +130.

Favorite at -150 → 150 ÷ (150 + 100) = 60.0%
Underdog at +130 → 100 ÷ (130 + 100) = 43.5%
Total → 103.5% (that 3.5% is the vig)

Now normalize — divide each by 1.035 (i.e. by the total) to get the fair, no-vig probability:

Favorite: 60.0% ÷ 103.5% = 57.97%
Underdog: 43.5% ÷ 103.5% = 42.03%
Total → 100.0% ✓

So the market's true read on this favorite isn't 60% — it's ~58%. The other ~2% was vig. That no-vig number is what you actually compare your own estimate against.

Three-way markets (soccer)

Soccer moneylines have three outcomes — home win, draw, away win — so the prices sum across all three (often to 105–108%, since more outcomes usually means more juice). The math is identical: convert each of the three to an implied probability, add them up, and divide each by the total to normalize back to 100%. Devigging three-way lines is just the two-way method with one more term.

Why the no-vig line is your fair-value benchmark

Here's the payoff. The devigged, no-vig probability from a sharp, high-limit market is the closest thing to the "true" probability of an event that exists. It represents the collective, money-weighted opinion of the entire market with the house's cut stripped away.

That gives you a yardstick. If you can find the same bet priced better than its no-vig fair value — at a softer book, or at a different price earlier in the week — you've found positive expected value. The no-vig line is also the foundation of arbitrage and the cleanest way to measure closing line value: did you beat the fair number the market settled on?

Prediction markets and effective hold

This is where venues like Polymarket get interesting. On a prediction market, prices are set by traders buying and selling shares, not by a book padding a margin. On a liquid market the YES and NO prices tend to sum much closer to 100% (say ~101%) than a sportsbook's 104.76% on the same event — a lower effective hold. Less vig means less edge you have to overcome before a bet is +EV, which is a structural reason sharp bettors watch these markets. It's not magic — thin or illiquid markets can carry wide spreads — but on a deep market you're often paying a smaller toll.

Do the math without the math

You don't need to run these divisions by hand every time. Cobia's devig calculator in the Tools tab converts any American, decimal, or fractional line into its implied and no-vig probabilities for two- and three-way markets — so you can price a bet against the fair number in seconds and instantly see how much juice you're being charged.

Key takeaways

The vig (juice/hold) is the book's built-in commission, baked into every price.
A -110/-110 line implies 52.38% each side — a total of 104.76%, roughly a 4.5% hold.
You must hit 52.38% at -110 just to break even — the gap over 50% is the vig.
Devigging = normalize each side's implied probability by the total to recover the fair, no-vig price.
Three-way (soccer) markets use the same method with one extra outcome.
The no-vig line is your best fair-value benchmark; prediction markets like Polymarket often carry a lower effective hold.

Cobia prices every pick against the no-vig fair line — and grades it in public.

Devig calculator built in. No fake units, no deleted losers.

Start free at cobiapicks.com