Prediction Markets vs Sportsbooks: Kalshi Odds Gaps Today
Updated August 13, 2026 · 13 min read · by Jake Hari
Every day, two completely different pricing machines put a number on the same baseball games. Sportsbooks build a moneyline, pad it with vig, and shade it toward whatever their customers like to bet. Prediction markets like Kalshi let traders set the price directly, with no vig and a visible order book. Most days those two machines land within a penny of each other. Some days they do not, and the only way to know which days is to check every game, both directions, with the vig stripped out. That is what this page does: the prediction markets vs sportsbooks question, answered with arithmetic instead of vibes. We pull the full moneyline board from 25+ sportsbooks and the matching Kalshi MLB odds, de-vig the books, and publish every gap, every day, on this URL.
The Quick Answer
2 of the 30 team prices across 15 matched games clear the 2-point bar today — the widest is Miami Marlins at -2.5 points — and the gaps run in both directions, so check the board before assuming either venue is the cheap one. The more interesting finding is at the edge of the board, where Kalshi is already running two-sided markets on 6 games the sportsbooks have barely posted. The full board, the receipts behind every number, and where the pennies sit are below.
If event contracts are new to you, here is how Kalshi's sports markets actually work. Every price on this page was fetched from the OddsShopper odds feed and Kalshi's public API at the timestamp stamped on the board itself, and the tables are generated straight from those fetches. Nothing on this board is typed in by hand.
How To Read This Board
Three columns carry the whole comparison, and each one is labeled by what it actually is rather than what would sound most impressive.
Kalshi Mid is the midpoint between the best live bid and best live ask in that team's order book, in cents. A 52.5¢ mid means the market's resting orders center on a 52.5% chance. The mid is not a price you can necessarily trade at; you buy at the ask and sell at the bid, and on thin markets that spread is part of the cost.
Book Fair is the best available sportsbook price on each side of the game, converted to implied probability, then normalized so the two sides sum to 100%. That normalization is the standard two-way de-vig: it strips the bookmaker's margin out of the quoted prices. Because we take the single best price on each side across the whole market, the synthetic hold being removed is already small, usually one to three points on an MLB moneyline.
Gap is Kalshi Mid minus Book Fair, in points of win probability. A negative gap means the exchange prices that team below the books' vig-free number, so the prediction market side is the cheaper way to back that team. A positive gap means the books are cheaper.
One thing a fair probability is not: a betting signal. De-vigging tells you what the books think happens after you remove their margin. It does not tell you the books are right, and a two-point gap is not a two-point edge. Fees also change the math on the exchange side. Kalshi charges trading fees that scale with the price of the contract, which eats part of any small gap, and we walk through exactly how that arithmetic compares in Kalshi fees vs sportsbook vig.
The Board
Board prices as of September 26, 2026, 5:06 PM ET · covers today's remaining pregame games plus tomorrow's full slate (15 matched games) · refreshes every morning, and again in the late afternoon when slates fill in.
| Matchup | First Pitch | Team | Kalshi Mid | Book Fair | Gap |
|---|---|---|---|---|---|
| ATL @ MIA | Sun 3:10 PM ET | Braves | 52.5¢ | 50.0% | +2.5 |
| Marlins | 47.5¢ | 50.0% | -2.5 | ||
| TB @ PHI | Sat 7:15 PM ET | Rays | 47.5¢ | 46.5% | +1.0 |
| Phillies | 53.5¢ | 53.5% | +0.0 | ||
| TB @ PHI | Sun 3:05 PM ET | Rays | 45.5¢ | 45.5% | +0.0 |
| Phillies | 53.5¢ | 54.5% | -1.0 | ||
| HOU @ ATH | Sat 9:40 PM ET | Astros | 60.5¢ | 59.6% | +0.9 |
| Athletics | 39.5¢ | 40.4% | -0.9 | ||
| AZ @ SD | Sat 8:40 PM ET | D-backs | 45.5¢ | 46.2% | -0.7 |
| Padres | 53.5¢ | 53.8% | -0.3 | ||
| STL @ MIL | Sun 3:10 PM ET | Cardinals | 31.5¢ | 32.2% | -0.7 |
| Brewers | 68.5¢ | 67.8% | +0.7 | ||
| PIT @ DET | Sun 3:10 PM ET | Pirates | 55.0¢ | 55.2% | -0.2 |
| Tigers | 45.5¢ | 44.8% | +0.7 | ||
| BAL @ NYY | Sun 3:20 PM ET | Orioles | 43.5¢ | 44.1% | -0.6 |
| Yankees | 56.5¢ | 55.9% | +0.6 | ||
| COL @ CWS | Sat 7:10 PM ET | Rockies | 30.5¢ | 31.0% | -0.5 |
| White Sox | 69.5¢ | 69.0% | +0.5 | ||
| LAA @ SEA | Sat 9:40 PM ET | Angels | 40.5¢ | 41.0% | -0.5 |
| Mariners | 59.5¢ | 59.0% | +0.5 | ||
| LAA @ SEA | Sun 3:10 PM ET | Angels | 38.0¢ | 38.5% | -0.5 |
| Mariners | 61.5¢ | 61.5% | +0.0 | ||
| STL @ MIL | Sat 7:10 PM ET | Cardinals | 40.5¢ | 40.9% | -0.4 |
| Brewers | 59.5¢ | 59.1% | +0.4 | ||
| NYM @ WSH | Sun 3:05 PM ET | Mets | 50.5¢ | 50.1% | +0.4 |
| Nationals | 49.5¢ | 49.9% | -0.4 | ||
| COL @ CWS | Sun 3:10 PM ET | Rockies | 34.0¢ | 34.3% | -0.3 |
| White Sox | 65.5¢ | 65.7% | -0.2 | ||
| CLE @ KC | Sat 7:10 PM ET | Guardians | 50.5¢ | 50.4% | +0.1 |
| Royals | 49.5¢ | 49.6% | -0.1 |
Bolded gaps clear the 2-point bar we treat as meaningful. Everything else is inside the noise band where fees and spread eat the difference before you do.
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Every market above links to our full AI model verdict; browse them all on the OddsShopper prediction markets hub, and see how every settled call actually scored on the full graded scoreboard.
The Receipts
Every number above traces to a specific book and a specific order book. The wide table scrolls on a phone; the point of publishing it is that you can check any row against the live market yourself.
| Game | Team | Best Book Price | Implied | De-Vig Fair | Kalshi Bid/Ask | Kalshi Mid |
|---|---|---|---|---|---|---|
| ATL@MIA 09-27 | Braves | -110 (Fanatics) | 52.4% | 50.0% | 52¢ / 53¢ | 52.5¢ |
| ATL@MIA 09-27 | Marlins | -110 (Fanatics) | 52.4% | 50.0% | 47¢ / 48¢ | 47.5¢ |
| TB@PHI 09-26 | Rays | +114 (Betcris) | 46.7% | 46.5% | 47¢ / 48¢ | 47.5¢ |
| TB@PHI 09-26 | Phillies | -116 (FanDuel) | 53.7% | 53.5% | 53¢ / 54¢ | 53.5¢ |
| TB@PHI 09-27 | Rays | +112 (Caesars) | 47.2% | 45.5% | 45¢ / 46¢ | 45.5¢ |
| TB@PHI 09-27 | Phillies | -130 (Fanatics) | 56.5% | 54.5% | 53¢ / 54¢ | 53.5¢ |
| HOU@ATH 09-26 | Astros | -150 (BetRivers) | 60.0% | 59.6% | 60¢ / 61¢ | 60.5¢ |
| HOU@ATH 09-26 | Athletics | +146 (Pinnacle) | 40.7% | 40.4% | 39¢ / 40¢ | 39.5¢ |
| AZ@SD 09-26 | D-backs | +116 (Betcris) | 46.3% | 46.2% | 45¢ / 46¢ | 45.5¢ |
| AZ@SD 09-26 | Padres | -117 (BetRivers) | 53.9% | 53.8% | 53¢ / 54¢ | 53.5¢ |
| STL@MIL 09-27 | Cardinals | +200 (Fanatics) | 33.3% | 32.2% | 31¢ / 32¢ | 31.5¢ |
| STL@MIL 09-27 | Brewers | -235 (Caesars) | 70.1% | 67.8% | 68¢ / 69¢ | 68.5¢ |
| PIT@DET 09-27 | Pirates | -134 (Caesars) | 57.3% | 55.2% | 54¢ / 56¢ | 55.0¢ |
| PIT@DET 09-27 | Tigers | +115 (Fanatics) | 46.5% | 44.8% | 45¢ / 46¢ | 45.5¢ |
| BAL@NYY 09-27 | Orioles | +117 (OnyxOdds) | 46.1% | 44.1% | 43¢ / 44¢ | 43.5¢ |
| BAL@NYY 09-27 | Yankees | -140 (Fanatics) | 58.3% | 55.9% | 56¢ / 57¢ | 56.5¢ |
| COL@CWS 09-26 | Rockies | +217 (Circa) | 31.5% | 31.0% | 30¢ / 31¢ | 30.5¢ |
| COL@CWS 09-26 | White Sox | -235 (Unibet) | 70.1% | 69.0% | 69¢ / 70¢ | 69.5¢ |
| LAA@SEA 09-26 | Angels | +140 (Bet99ON) | 41.7% | 41.0% | 40¢ / 41¢ | 40.5¢ |
| LAA@SEA 09-26 | Mariners | -150 (Circa) | 60.0% | 59.0% | 59¢ / 60¢ | 59.5¢ |
| LAA@SEA 09-27 | Angels | +150 (Fanatics) | 40.0% | 38.5% | 37¢ / 39¢ | 38.0¢ |
| LAA@SEA 09-27 | Mariners | -176 (Caesars) | 63.8% | 61.5% | 61¢ / 62¢ | 61.5¢ |
| STL@MIL 09-26 | Cardinals | +141 (Caesars) | 41.5% | 40.9% | 40¢ / 41¢ | 40.5¢ |
| STL@MIL 09-26 | Brewers | -150 (Betcris) | 60.0% | 59.1% | 59¢ / 60¢ | 59.5¢ |
| NYM@WSH 09-27 | Mets | -109 (Caesars) | 52.2% | 50.1% | 50¢ / 51¢ | 50.5¢ |
| NYM@WSH 09-27 | Nationals | -108 (Caesars) | 51.9% | 49.9% | 49¢ / 50¢ | 49.5¢ |
| COL@CWS 09-27 | Rockies | +181 (Caesars) | 35.6% | 34.3% | 33¢ / 35¢ | 34.0¢ |
| COL@CWS 09-27 | White Sox | -213 (Caesars) | 68.1% | 65.7% | 65¢ / 66¢ | 65.5¢ |
| CLE@KC 09-26 | Guardians | -103 (Betcris) | 50.7% | 50.4% | 50¢ / 51¢ | 50.5¢ |
| CLE@KC 09-26 | Royals | +100 (Circa) | 50.0% | 49.6% | 49¢ / 50¢ | 49.5¢ |
Where The Money Sits Today
- Biggest prediction-market discount: Miami Marlins (Atlanta Braves @ Miami Marlins, Sun 3:10 PM ET). Kalshi's mid is 47.5¢ against a best-book de-vig fair of 50.0% (best book price -110 at Fanatics) — the exchange prices this team 2.5 points below the books' vig-free number.
- Biggest sportsbook discount: Atlanta Braves (Atlanta Braves @ Miami Marlins, Sun 3:10 PM ET). The books' de-vig fair is 50.0% while Kalshi's mid sits +2.5 points higher at 52.5¢ — here the sportsbook side (-110 at Fanatics) is the better number, not the exchange.
- Of 30 team prices on this board, 2 clear the 2-point bar the board treats as meaningful; the rest sit inside it, which is what an efficient market pair looks like.
- 6 games where the exchange is quoting and the books mostly are not yet: Los Angeles Dodgers @ San Francisco Giants (Sun 3:05 PM ET: Dodgers 74¢, Giants 26¢); Houston Astros @ Oakland Athletics (Sun 3:05 PM ET: Astros 56¢, Athletics 44¢); Cincinnati Reds @ Toronto Blue Jays (Sun 3:07 PM ET: Reds 40¢, Blue Jays 60¢); Texas Rangers @ Minnesota Twins (Sun 3:10 PM ET: Rangers 52¢, Twins 48¢); Cleveland Guardians @ Kansas City Royals (Sun 3:10 PM ET: Guardians 57¢, Royals 42¢); Arizona Diamondbacks @ San Diego Padres (Sun 3:10 PM ET: D-backs 46¢, Padres 54¢). Kalshi runs a two-sided market on each while fewer than two traditional sportsbooks have posted a moneyline — the exchange is routinely first to price a slate.
That last bullet is the quiet story of this board. Baseball moneylines are one of the most efficiently priced markets either venue offers, so on a normal day the value of this page is not a fat arbitrage; it is knowing which side of a one-point split you are on, and catching the days when the machines actually disagree. When a real gap opens, it will be bolded in the table above, and this page will already be here.
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Why The Two Venues Disagree At All
If both prices come from smart money, why is there ever a gap? Four mechanical reasons, none of them mysterious.
Different cost structures. A sportsbook's margin lives inside the price: quote both sides of a coin flip at -105 and the vig is invisible until you de-vig it. An exchange's cost lives outside the price, as a trading fee plus the bid-ask spread. Two venues can believe the exact same probability and still quote numbers a point apart because the costs sit in different places.
Different flow. Books shade lines toward the public side because their customers arrive wanting favorites and big names. Exchange prices move only when someone actually trades, so a team the public loves can be a point more expensive at the book than on the exchange without any disagreement about the baseball.
Different reaction speeds. Books employ traders and copy each other within minutes. Exchange prices wait for a participant to show up. On lightly traded games, Kalshi's mid can sit stale for an hour, which is why the board shows the bid and ask, not just the mid, in the receipts table.
Different posting schedules. Books hold a line back when a starting pitcher is unconfirmed. The exchange does not need a trader's permission to exist, so its markets are often live and two-sided a day before most books post. The callouts above list the games currently in that state. If you want to know where a game will likely open, the exchange frequently knows first.
For the deeper version of this comparison, including limits, account treatment, and when each venue is the right tool, see Kalshi vs sportsbook odds.
What Would Move This Board
Gaps on this page are born from news, and they close fast. The concrete triggers worth watching:
- Starter announcements. The moment an unconfirmed pitcher becomes confirmed, the books post, and the pm-only games above become matched rows with real gaps for a few minutes.
- Lineup cards, roughly two hours before first pitch. A star sitting moves a moneyline one to two points, and the venue that reprices second is briefly mispriced against the one that repriced first.
- Late-afternoon volume. Exchange order books are thinnest in the morning. As game time approaches, spreads tighten from several cents to one, and mids become trustworthy. This board refreshes in the late afternoon for exactly that reason.
- Weather. Wind and rain reprice totals first, but a probable postponement moves moneylines too, and settlement rules on postponed games differ between a book and an exchange. Check the contract's own rules text before assuming they match.
How This Board Gets Built
The pipeline is deterministic and runs the same way every day: fetch every book's moneyline for every pregame game in the window from the OddsShopper odds feed, fetch the matching Kalshi game markets and read each order book directly, match the games by team and start time, de-vig the best book prices, and emit the tables you see above. Prediction market venues that appear on odds screens, including Kalshi itself, Polymarket, and sweepstakes apps, are excluded from the sportsbook side of the comparison, because a benchmark that contains the thing being benchmarked is not a benchmark. When today's remaining slate is short, the board widens to tomorrow's games and says so in the stamp line; that is the case on today's board.
No probability on this page is a prediction of ours, and nothing here is a promise that a gap will persist or profit anyone. It is an honest measurement, re-run daily. Our AI panel's own calls are held to the same standard: every one is publicly graded against real market settlements on the model verdict scoreboard, where every number is recomputed from stored rows.
If you want the same comparison live, on your own filters, the OddsShopper MLB odds screen shows every book's number on one screen, including the exchanges, with the de-vigged fair probability computed for you across every market we track, not just moneylines. It is the tool this board is built from.
Prediction Markets vs Sportsbooks FAQ
Are prediction market odds better than sportsbook odds? Neither venue is reliably cheaper. On MLB moneylines the gap between Kalshi's mid and the books' de-vigged fair probability is usually a point or two at most, and it runs in both directions. Which venue is better on a given game is an empirical question, which is why this board exists.
Why are Kalshi odds different from sportsbook odds? Different cost structures (vig inside the price vs fees and spread outside it), different customer flow, different reaction speeds, and different posting schedules. The section above walks through each mechanism.
Does removing the vig make the sportsbook number the true probability? No. De-vigging removes the bookmaker's margin from the quoted prices, which makes the comparison fair, but the result is still just the market's opinion with the costs stripped out. A fair probability is a reference point, not a betting threshold.
The Bottom Line
Most days, prediction markets and sportsbooks price baseball within a rounding error of each other, and anyone telling you otherwise has not de-vigged the books. The gaps that matter show up around news, on thin markets, and on slates the books have not fully posted, which is where an exchange that is always on quietly earns its keep. This page exists so you never have to take anyone's word for which venue is cheaper today, ours included. The board above is the answer, with receipts, and it will say something different tomorrow.
Event contracts are CFTC-regulated financial products offered on exchanges such as Kalshi, available to eligible U.S. residents 18+. Prices move constantly, and the de-vigged fair probabilities computed here are model estimates, not predictions of fact and not financial advice. Numbers shown were fetched at the timestamp on the board and will have changed by the time you read this.
