Arbitrage Scanner

Prediction market arbitrage combines event contracts whose total purchase cost, including trading costs, is less than the position pays under every possible outcome. One form pairs Yes in one market with No in another market on the same question. When both contracts settle on the same terms, one of those positions pays $1. Related questions can also create arbitrage opportunities, depending on which outcomes can occur together.

Choose an event to use as your starting point. The scanner suggests related events from both venues, and you can select a counterpart or search for another one. Each comparison analyzes two markets, with one contract in each, showing their price histories and the cost and payout of different Yes and No positions. You can keep the first event selected while investigating other counterparts or change the selected outcome on either side.

Yes. A pair can cover related questions with different thresholds or deadlines, on the same venue or across Polymarket and Kalshi. Each market’s full rules and resolution sources are available in Event details without leaving the comparison. You can check how their settlement conditions relate, including differences that could make the markets resolve differently. The payout grid shows how a position in both markets would perform under those outcomes.

Yes. Both sides can come from Polymarket, both can come from Kalshi, or the pair can cross venues. To compare two outcomes within one event, find the same event in Search, select it for the second side, and choose a different market for each side. This lets you compare candidates within an election or thresholds within a price ladder. The same price-history views and arbitrage calculator apply to each pairing.

Yes. The Search tab lets you find another open event on either venue, with results you can sort by relevance, activity, or closing time. Including market rules can find a contract through a resolution source or threshold that is absent from the event title. Either event in the pair can be replaced as you find other markets to investigate.

The cost grid shows the estimated cost of buying one contract in each selected market for Yes/Yes, No/No, Yes/No, and No/Yes positions. Selecting a position opens a payout grid showing all four combinations of Yes and No resolutions. It assumes a winning contract pays $1 and a losing contract pays nothing, so the pair can pay $2, $1, or nothing. Each cell shows that payout and the gain or loss after subtracting the estimated purchase cost. Refunds or partial settlements specified in a market’s rules are outside this model.

The calculator uses each market’s displayed chance as the estimated Yes price, rounded to cents, and subtracts it from $1 to estimate the No price. A displayed chance of 40%, for example, gives a Yes cost of 40¢ and a No cost of 60¢. The cost of the pair is the sum of the two selected contracts. These estimates exclude the bid/ask spread and venue fees, and the price available for an order can differ from the displayed price.

Each calculation assumes one contract in each market. The scanner does not size a trade or estimate how much can be bought at a particular price. Volume and open interest provide information about market activity, while the cost and payout grids show the arithmetic for the selected pair.

Yes. The Chance view plots both selected markets on the same timeline using their available price history. The Gap view subtracts the second market’s probability from the first and follows the difference in percentage points. A positive gap means the first market has the higher Yes price; a negative gap means the second does. Together, the views show where the probabilities move together or diverge and whether the price difference has widened or narrowed. The same odds comparison is available for two markets on one venue.

The scanner uses market data from Polymarket and Kalshi. The comparison’s Last updated time reflects the older update of the two selected markets, so you can see how current the pair is as a whole. Data is refreshed periodically, and displayed prices can differ from those currently available on the venue.

Yes. You can compare sports event contracts on Polymarket and Kalshi, including markets concerning the same match or related outcomes. The tool shows the contract prices and the payouts for a position in both markets. Its coverage is prediction markets, so the comparisons use event contracts rather than sportsbook odds.

Yes. You can compare event contracts about crypto assets on Polymarket and Kalshi, including contracts with different price thresholds or deadlines. The price history and payout grid help you examine the relationship between those markets. The scanner compares the prices of the event contracts; it does not compare the cost of buying a coin on different crypto exchanges.

Yes. You can compare markets for the same candidate across Polymarket and Kalshi, or select different candidates within an election event. Each pair has an odds comparison and a calculation of its possible payouts. The market rules let you check which election or stage of a race each contract covers before interpreting the price difference.

No. The Arbitrage Scanner provides market comparisons and cost and payout calculations for your research. It does not submit orders or execute trades. Each event’s details include a link to its venue, where trading takes place.

Yes. You can use the Arbitrage Scanner without an account, including the odds comparison, arbitrage calculator, and market rules. A free account lets you browse beyond the first page of search results.