Cardinals vs Reds Prediction Market Odds, August 18, 2026
| Spread | Total | ML | Best ML | |
|---|---|---|---|---|
▶Cardinals | -1.5 40%41% | O 1 50%49% | 53%52% | 53% Kalshi |
▶Reds | +1.5 60%59% | U 1 50%51% | 48%49% | 49% Polymarket |
| Spread | Total | Moneyline | Best ML | |
|---|---|---|---|---|
▶St. Louis Cardinals | -1.5 | O 1 | 53% Kalshi | |
▶Cincinnati Reds | +1.5 | U 1 | 49% Polymarket |
No player props available for this game.
St. Louis is the narrow side at Great American Ball Park on Tuesday, August 18, 2026, priced at 53c on Kalshi and 52c on Polymarket against a Cincinnati Reds contract at 48c and 49c. That is a four-cent edge on a Cardinals club that is 64-62 overall and 32-28 on the road against a Reds club that is 60-65 and 31-34 at home. Kyle Leahy (9-4, 3.38 ERA) faces Andrew Abbott (6-7, 4.13 ERA). Roughly $8.1K in lifetime volume has traded across the full board, and the live board above carries current prices on every line.
St. Louis walks into Cincinnati on Tuesday, August 18, 2026 with a 64-62 record, third place in the NL Central, and a road mark of 32-28 that is the better half of its season. Cincinnati sits fifth in the division at 60-65 and has been a below .500 team in its own park at 31-34. The standings say three and a half games. The board says close to nothing: the Cardinals moneyline is a 52.5c cross-platform average, the Reds moneyline is 48.5c, and Kalshi and Polymarket are within a single cent of each other on both sides.
Cardinals vs Reds Market Context
The Cardinals vs Reds moneyline is the tightest kind of board this API surfaces. Kalshi has St. Louis at 53c and Cincinnati at 48c. Polymarket has St. Louis at 52c and Cincinnati at 49c. Both books add to 101c, which is normal two-sided pricing, and the one-cent disagreement between them is inside the noise of a thin midweek market. There is no venue-selection story here. The read is the same on both platforms: a favorite priced at roughly 52% to 53% implied, which is about as small a favorite as baseball produces.
The run line is where the market draws the sharper distinction. St. Louis at -1.5 trades at 40.5c (40c Kalshi, 41c Polymarket) while Cincinnati at -1.5 trades at 32c on both books. The 8.5c gap between the two run lines is more than double the 4c gap on the moneyline. That is the market saying St. Louis is meaningfully more likely to win by multiple runs, not just more likely to win, which is the shape you get when one side has the better starter and the deeper offensive profile rather than a large overall talent edge.
The total is set high. Over 8.5 runs prices at 53c on both platforms, Over 7.5 sits at 60.5c, and Over 9.5 drops to 42c. Stacking those three points puts the market's central expectation right around nine runs, which is a hitter's-park number and consistent with how Great American Ball Park has played. The first-inning run market is effectively a coin flip at 49.5c (50c Kalshi, 49c Polymarket). Polymarket's five-inning ladder has St. Louis leading after five at 44c, Cincinnati at 41c, and a tie at 18c, which is a slightly flatter version of the same read the full-game moneyline gives.
Cardinals vs Reds Pitching Matchup
Kyle Leahy takes the ball for St. Louis at 9-4 with a 3.38 ERA. Andrew Abbott answers for Cincinnati at 6-7 with a 4.13 ERA. The 0.75-run ERA separation is the single cleanest justification for the four-cent moneyline edge, and it is roughly the size of edge a starter differential of that scale is worth before park and bullpen adjustments. Abbott gets the home park, which cuts the other way on a total already priced near nine runs.
On line movement, the Cardinals moneyline has been flat. Kalshi's St. Louis contract has printed 53c on every snapshot in the current window, and the Cincinnati side has held at 48c across the same span. Nothing in the price series suggests late information moving through the board. The volume distribution is lopsided in a way worth noting: the Cardinals moneyline carries $7.2K of the board's $8.1K lifetime total, with the Cincinnati contract at $658 and the run line at $981. The favorite side is where the liquidity is, and the alternate totals below Over 7.5 are largely untraded.
When the Cardinals vs Reds Market Resolves
The moneyline resolves to the team that wins the game at Great American Ball Park on Tuesday, August 18, 2026, first pitch scheduled for 6:40 p.m. ET. Each winning contract pays $1 per share and the losing side settles at $0. The run line settles on the final margin, so St. Louis (-1.5) needs a win by two or more runs. Totals settle on combined runs scored in the full official game, with the 8.5 line resolving Over at nine runs or more. Both Kalshi and Polymarket settle from the official MLB final score once the game is declared complete. If the game is postponed, suspended, or shortened, each platform applies its own published rules for rescheduled and shortened contests rather than settling on a partial score.
Key Cardinals vs Reds Catalysts
Starting pitching gap: Leahy at 3.38 ERA against Abbott at 4.13 is the whole case for the Cardinals price, and a late scratch on either side reprices the board immediately.
Park and total: Over 8.5 at 53c means the market expects nine runs in a park that supports that number, so weather and wind direction in Cincinnati are live inputs on the total.
Run line versus moneyline: the 8.5c spread between the two -1.5 contracts is wider than the 4c moneyline spread, so bettors who agree with the Cardinals read get a cleaner expression of it on the run line.
Liquidity concentration: the Cardinals moneyline holds $7.2K of $8.1K in board volume, so the Reds side and the alternate totals move on small size.
Standings stakes: St. Louis at 64-62 is still inside the wild-card conversation while Cincinnati at 60-65 is playing out the string, which shapes bullpen usage and late-inning aggression on both sides.
Related Cardinals vs Reds Markets
Season-long context for both clubs lives on the team hubs: the St. Louis Cardinals market page and the Cincinnati Reds market page collect every active contract on each franchise. The October question is priced directly on the Cardinals playoff market and the Reds playoff market, which is where a game like this one actually shows up in the futures. For the broader field, the NL pennant market tracks the full National League contender set, and the MLB hub carries every game board and futures market on the calendar.
Resolution Criteria
The moneyline resolves to the team that wins the game between the St. Louis Cardinals and Cincinnati Reds at Great American Ball Park on Tuesday, August 18, 2026, with first pitch scheduled for 6:40 p.m. ET. The winning team's contract pays $1 per share and the losing team's contract settles at $0. Run line contracts settle on the final margin, so the St. Louis (-1.5) contract requires a Cardinals win by two runs or more. Total contracts settle on combined runs scored across the full official game, with Over 8.5 resolving Yes at nine runs or more. First-inning and first-five-innings contracts settle on the score at the end of that specific segment. Both Kalshi and Polymarket settle from the official MLB final score once the game is declared complete, and each platform applies its own published rules for postponed, suspended, or shortened games rather than settling on a partial score.
Key Factors
- Kyle Leahy (9-4, 3.38 ERA) vs Andrew Abbott (6-7, 4.13 ERA) is the pitching edge behind the four-cent Cardinals price
- Over 8.5 runs at 53c prices a hitter's-park total, making Cincinnati weather and wind a direct input
- Cardinals -1.5 at 40.5c vs Reds -1.5 at 32c is an 8.5c gap, wider than the 4c moneyline gap
- Kalshi and Polymarket sit within 1c on both moneyline sides, so there is no cross-platform price separation to work with
- Cardinals moneyline holds $7.2K of the board's $8.1K lifetime volume, leaving the Reds side and alternate totals thin
- St. Louis at 64-62 is still in wild-card range while Cincinnati at 60-65 is not, which shapes late-inning bullpen usage
What are the current Cardinals vs Reds odds?
As of August 18, 2026, St. Louis trades at 53c on Kalshi and 52c on Polymarket, a 52.5c cross-platform average. Cincinnati trades at 48c on Kalshi and 49c on Polymarket, a 48.5c average. The live board above carries the current prices.
Who is favored in Cardinals vs Reds?
St. Louis is the favorite at roughly 53% implied probability, a four-cent edge over Cincinnati at 48.5c. The Cardinals are 64-62 and 32-28 on the road, while the Reds are 60-65 and 31-34 at Great American Ball Park.
Where can I trade the Cardinals vs Reds market?
Both Kalshi and Polymarket list the game. Kalshi carries the moneyline, run line, full-game and first-five-innings totals, and team totals. Polymarket carries the moneyline, run line, main totals, and a five-inning leader market that prices a tie at 18c.
When does the Cardinals vs Reds market resolve?
The game is scheduled for Tuesday, August 18, 2026 at Great American Ball Park with a 6:40 p.m. ET first pitch, and contracts settle from the official MLB final score once the game is declared complete.
What is the Cardinals vs Reds run line and total?
St. Louis at -1.5 trades near 40.5c and Cincinnati at -1.5 near 32c. The main total is Over 8.5 runs at 53c on both platforms, with Over 7.5 at 60.5c and Over 9.5 at 42c.
What should I watch before Cardinals vs Reds resolves?
Watch for a late change to either probable starter, since the 0.75-run ERA gap between Leahy and Abbott is what the four-cent moneyline edge is paying for. Cincinnati game-time weather is the other live input on a total already priced near nine runs.