Polymarket arbitrage calculator
If you can buy YES and NO on the same outcome for less than $1 combined, after fees, the profit is locked in. On Polymarket itself this is rare and short-lived; across platforms it is more common but riskier.
What can go wrong
- Different rules. Two platforms can resolve “the same” question differently. Compare the exact wording and sources.
- Execution. Prices move while you fill the second leg.
- Capital lock-up. Your money is tied up until resolution; a 1% edge over six months is a weak return.
- Transfer costs. Moving money between platforms costs fees and time.
This calculator applies Polymarket's fee to both legs. If one leg is on Kalshi or Polymarket US, use that platform's fee instead: their formulas and rounding differ. Read the full arbitrage guide.
Ready to try it? Check it is available where you live, then open Polymarket.
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