Kalshi vs Polymarket — MLB Price Gaps
MLB runs daily from April through October — roughly 15 games a night — which makes it the steadiest source of Kalshi–Polymarket price gaps on the board. Below are the live cross-exchange gaps on today’s games. MLB is a Kalshi↔Polymarket-only lane (no sportsbook foil), so every number here is exchange-vs-exchange.
Live MLB Price Gaps: Kalshi vs Polymarket
Updated May 30, 11:30 PM ETWhere Kalshi and Polymarket price the same game differently right now. Two exchanges disagreeing on the same outcome is a genuine cross-exchange gap — unlike a sportsbook line, which bakes in vig (the house edge). The book's implied price is shown for reference so you can see how much wider it sits.
| Pick | Kalshi | Polymarket | Gap | Book (vig) |
|---|---|---|---|---|
| Atlanta Braves Atlanta vs Cincinnati · MLB | 56¢ | 55¢ | 1pp | — |
Gaps are the difference in implied probability between the two exchanges on the same game, ranked by symmetric KL divergence. Polymarket prices come from the latest hourly snapshot; Kalshi prices are live. Sportsbook prices are de-vigged for a fair comparison. Informational only — verify resolution terms before trading.
How we compute the gap
For each MLBgame listed on both exchanges, we take Kalshi's live implied probability and Polymarket's latest snapshot probability for the same team, then measure how far apart they are. Games are ranked by symmetric KL divergence — a measure of how much the two price distributions disagree — and we surface the biggest gaps first. A “gap” here is the difference in implied probability between the two exchanges, in percentage points.
A cross-exchange gap is not the same as a sportsbook edge. Two exchanges disagreeing is a genuine signal; a sportsbook line sitting wider is mostly vig — the house margin baked into both sides. That's why we lead with the Kalshi–Polymarket comparison and show the book only for reference. Informational only — always verify resolution terms and liquidity before taking a position.
MLB: Kalshi vs Polymarket FAQ
Is Kalshi or Polymarket cheaper for MLB?
With ~15 games a day, gaps open and close fast. The live table flags the cheaper exchange per game. Because neither exchange charges vig, the gap is the true price difference, not a house margin.
How many MLB games show gaps each day?
It varies with how many games clear our volume floor on both exchanges, but MLB’s daily schedule means there is almost always something to compare from April through October — the bridge between the end of NBA/NHL in June and the NFL kickoff in September.
Why is there no sportsbook column for MLB?
MLB is run as a Kalshi↔Polymarket-only comparison to keep it free of third-party odds costs. The two exchanges are the sharper read anyway — a sportsbook line would only show you the vig.
How current are the MLB prices?
Kalshi prices are live; Polymarket prices come from the latest hourly snapshot. The table stamps its last update time.