How to Devig Odds for Polymarket: The 1-Minute Fair Price Check

Atalanta to win at Fiorentina on 29 October 2026 cost 33 cents a share on Polymarket. Pinnacle's odds for the same result, 3.03, also read as a 33% chance. So the price looks fair. It isn't: once you devig Pinnacle's odds and add Polymarket's fee, you'd pay about 2 cents a share more than the result is worth.

This guide is the one-minute check that shows it, done with three free OddsFantasy calculators. Every number below comes from prices recorded together at 12:14 UTC that day: Pinnacle's moneyline and Polymarket's best ask.

What does it mean to devig odds?

A bookmaker never offers fair odds. It builds in a margin, the vig (also called juice or overround), so the chances in its odds add up to more than 100%. Pinnacle's three odds for Fiorentina v Atalanta were:

• Fiorentina 2.35, a 42.55% chance as it stands
• Draw 3.71, 26.95%
• Atalanta 3.03, 33.00%

Together that's 102.51%. The extra 2.51% is the margin, a 2.45% vig. Devigging means taking it out, so what's left is the fair chance of each result. For the basics of the margin itself, see vig in sports betting.

Why use Pinnacle's odds?

Pinnacle is the bookmaker sharp bettors use as their reference: it takes large bets (up to $10,000 on this match) and keeps a small margin, which is why its devigged price is the usual free estimate of the fair chance. OddsFantasy's own value-bet feed scores every bet the same way: between 16 and 21 October 2026 it listed 32,107 pre-match value bets against Pinnacle's no-vig odds, with a median EV of just 2.36% (the data). Real edges are that small, so a 2-cent mistake on a 33-cent share is bigger than a typical one.

How to devig odds and check a Polymarket price

Step 1: Type the three odds into the vig calculator

Get Pinnacle's odds from pinnacle.com (under Soccer). Open the vig calculator, keep Decimal, and press + so Number of bets says 3 (a football match has three results). Type Pinnacle's odds: 2.35, 3.71 and 3.03.

Step 2: Read the fair price

Press Calculate. Atalanta is Bet 3:

• No-vig odds: 3.109, the fair odds
• Implied probability: 32.17%, the fair chance, which is a fair Polymarket price of about 32 cents
• Vig: 2.45%, the margin you removed

The calculator removes the margin additively: each result gives up an equal share of the extra.

Step 3: Add Polymarket's fee

Open the Kalshi and Polymarket fee calculator, pick Polymarket and Taker (fills now), and type price 33 and 100 shares. Polymarket charges takers on sports 0.05 × price × (1 − price) a share, so:

• Fee per share: 1.105¢
• Break-even probability: 34.11% (the chance the bet needs just to not lose)
• Odds after fee: 2.932

That's the price you really pay: about 34.1 cents for a result worth 32.2. More on the fee in Polymarket fees explained.

Step 4: Get the verdict in the EV calculator

Open the EV calculator. Bookmaker Odds is what you get, 2.932; True Odds is the fair price, 3.109; wager 100. Expected Value: −5.69%. On average you'd lose about $5.69 per $100. Skip it.

Step 5: Find the price worth paying

Back in the fee calculator, pick Maker (resting limit order). A limit order that waits in the book pays no fee on Polymarket. At 31 cents the odds are 3.226, and the EV calculator gives +3.76% against the fair 3.109. That's a price worth paying: set a limit order there and it only buys at 31 cents or better.

A second match: Everton v Newcastle

Same evening, EFL Cup. Pinnacle had Everton 2.35, draw 3.54, Newcastle 3.10 (a 2.97% vig). Devigged, Newcastle's fair chance is 31.24% (fair odds 3.201). Polymarket asked 32 cents; with the taker fee the odds drop to 3.022, and the EV is −5.59%. Skip it, or wait with a limit order below the fair price.

Across both matches, all six Polymarket asks failed the check once the fee was added (EV between −3.47% and −6.68%). That's normal: most prices are fair or a little dear, and the check is how you find the few that aren't.

The two mistakes

Using the raw odds. Put 3.03 into the odds to probability calculator and it says 33.00%, exactly the Polymarket price. That's why 33 cents looked fair: the vig is still inside. Always devig first.

Leaving out the draw. Devig only Fiorentina 2.35 and Atalanta 3.03 and the calculator shows a vig of −32.35% and fair odds that make no sense. A negative vig means a result is missing. A football moneyline has three results; enter all three.

Limits of the check

• The fair price is only as good as Pinnacle's odds and how fresh they are. Take both prices at the same moment.
• Different devig methods give slightly different fair prices, most on long shots and the draw. The vig calculator uses the additive method.
• The fee applies to taker orders. A resting limit order pays none, but it fills only when someone sells to you at your price, and may not fill at all.
• Polymarket's "win on" football markets settle on 90 minutes plus stoppage time, like Pinnacle's moneyline.

Let OddsFantasy do it for every match

Doing this by hand works for one match. The OddsFantasy +EV finder runs the same comparison against Pinnacle's no-vig odds across Polymarket and 50+ bookmakers all day, and the trading terminal places the order.

How do you devig odds?

Turn each result's odds into a chance (1 ÷ decimal odds), add them up, and remove the amount over 100% from the results. The OddsFantasy vig calculator does it: enter every result's odds and read the No-Vig Odds and Implied Probabilities.

What are no-vig fair odds?

The odds with the bookmaker's margin taken out, so the chances of all results add up to exactly 100%. Fiorentina v Atalanta's fair odds were 2.397, 3.829 and 3.109.

How do I know if a Polymarket price is good value?

Compare the fair chance from devigged Pinnacle odds with the price plus Polymarket's taker fee. If the price plus fee is below the fair chance, the EV is positive. Atalanta at 33 cents cost 34.11 cents with the fee against a fair 32.17, so it wasn't.

Does Polymarket charge a fee on sports?

Yes, on taker orders: 0.05 × price × (1 − price) per share, about 1.1 cents at 33 cents. Maker orders that rest in the book pay none.

Why devig all three results in football?

Because the vig is spread across all three. Leaving out the draw gives a negative vig and wrong fair odds.

Trade responsibly

Only stake what you can afford to lose, and check that Polymarket is available where you live.