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Arbitrage Scanner

Find guaranteed-profit opportunities across Kalshi and Polymarket. Enter prices from both platforms and see if an arbitrage exists after fees.

Kalshi

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Polymarket

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No arbitrage opportunity

Adjust prices to find an arb

Important Caveats

  • Execution risk: Prices may move before you fill both legs. Always fill the less liquid side first.
  • Settlement risk: Kalshi and Polymarket may interpret ambiguous event outcomes differently.
  • Liquidity: Order book depth may not support large sizes at quoted prices.
  • Capital lockup: Your funds are tied up until the event settles, which may be weeks or months.

How Prediction Market Arbitrage Works

Arbitrage exploits price differences between platforms. When the same event is priced differently on Kalshi and Polymarket, you can sometimes buy contracts on both sides (YES on one platform, NO on the other) for a combined cost less than $1.00. Since the payout is always $1.00 regardless of outcome, the difference is guaranteed profit.

There are two directions to check. Direction 1: Buy YES on Kalshi + buy NO on Polymarket (NO price = 100 - YES price). Direction 2: Buy NO on Kalshi + buy YES on Polymarket. The scanner checks both and picks the cheaper combination.

Fees are the primary arb killer. Kalshi charges 7% on profits, which reduces your net payout from the winning side. An arb that looks like 5 cents of profit pre-fees might net only 1-2 cents after fees — or nothing at all. This calculator shows you the real numbers after all fees.

Practical Tips

Fill the less liquid side first (usually Kalshi). Use limit orders, not market orders. Check that the order book has enough depth at the quoted price. The wider the arb, the more likely it persists — tiny arbs often disappear before you can fill both sides. And always verify both platforms are pricing the exact same event with the same settlement criteria.

Frequently Asked Questions

What is prediction market arbitrage?

Prediction market arbitrage is buying contracts on two different platforms so you profit regardless of the outcome. If the combined cost of YES on one platform and NO on the other is less than $1.00, you lock in the difference as guaranteed profit.

Can you arbitrage between Kalshi and Polymarket?

Yes, when the same event is listed on both platforms at different prices. Account for fees on both sides, execution risk (prices move), and settlement risk (platforms may resolve differently). Use limit orders and fill the less liquid side first.

How do fees affect arbitrage?

Fees can eliminate apparent arb opportunities entirely. Kalshi's 7% profit fee reduces your payout on the winning side. Always calculate net profit after all platform fees — this calculator does it for you.

What are the risks of arbitrage?

Key risks: execution risk (prices move before you fill both legs), settlement risk (platforms resolve differently), liquidity risk (can't fill at quoted prices), and capital lockup (money tied up until settlement). These risks are real — arbitrage is low-risk, not no-risk.