Prediction markets · NetArbs guide
Kalshi and Polymarket arbitrage: a practical checklist
Buying YES on one exchange and NO on another can appear to lock in a payout when the combined cost is below $1. The arithmetic is simple; verifying that the two contracts resolve the same way and can both be filled is the difficult part.
Confirm the event and resolution rules
Similar titles do not prove equivalence. Compare the exact outcome, date, timezone, source of truth, cancellation language and treatment of ties or extraordinary events. A YES/NO pair across different rules is a directional bet, not a locked payout.
Open both exact market links and read each contract before placing orders. NetArbs attaches the corresponding Kalshi and Polymarket links to a matched opportunity.
Price both legs at executable size
Use the available ask price and quantity for each side, not a last-traded price or a midpoint. Include each platform’s applicable trading fees and any funding or transfer costs. A quote for one share does not guarantee the same price for a larger stake.
If you place one leg first, the other can move or fail. Start with small size, check liquidity and plan how to handle an unmatched position.
Read the net edge, then verify it
NetArbs’ scanner computes pair cost, fees and an estimated net edge for matched markets. Those numbers are a live decision aid, not a guarantee of simultaneous fills or a promise of profit. Inspect both source pages and the current order books before acting.
Political, sports, weather and other categories can have different wording and resolution conditions; the same checklist applies to each.
See the method in NetArbs
Use the live tool to inspect the current prices and their sources. Quotes and payouts can change after this example was written.