Arbitrage Scanner
Compare price gaps on prediction markets. If YES and NO sum to less than 100 cents on the same market, or if two platforms price the same event differently, the scanner estimates the theoretical spread.
Enter the two prices. The scanner computes total stake, allocation across both legs, and locked-in return net of a typical fee assumption.
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Arbitrage FAQ
- What is prediction market arbitrage?
- Arbitrage is a price-gap opportunity that exists when the same event is priced differently across two venues, or when YES and NO prices on the same market sum to less than 100 cents. The math can show a theoretical locked return, but execution, fees, liquidity, and resolution differences still matter.
- How do I use this arbitrage calculator?
- Enter the YES and NO prices in cents, or enter prices for the same event from Polymarket and Kalshi. The calculator tells you whether a price gap exists, the dollar allocation across both sides, and the theoretical return before real-world friction.
- How common are arbitrage opportunities on Polymarket and Kalshi?
- Cross-platform arbitrage windows on high-volume markets typically close within minutes. They are most common on new listings, sports markets during live events, and political markets during breaking news. Scanning is a competitive game; getting alerts beats browsing manually.
- What fees should I factor in?
- Polymarket charges gas for deposits and withdrawals. Kalshi charges per-trade fees. A 2-cent theoretical arbitrage can easily turn into a 0.5-cent or negative real arbitrage after fees. Only chase spreads of 3 cents or more unless you have volume that amortizes fees.
- Are there risks to prediction market arbitrage?
- Yes. Platform risk (custody, withdrawal delays), execution risk (the spread closes while you are placing the second leg), and resolution risk (the two platforms may resolve an event differently based on different rulebooks). Always verify both platforms' resolution criteria match before entering an arb.
Worked example
Suppose on Polymarket, YES trades at 58¢. On Kalshi, the same event resolves with NO at 38¢. YES + NO = 96¢, meaning a 4-cent theoretical arbitrage per $1 staked across both legs.
Stake $580 on Polymarket YES and $380 on Kalshi NO. Total stake: $960. No matter which side resolves, you collect $1,000.
Net profit: $40 on $960 stake, or about 4.2% before fees, slippage, and resolution risk.