Arbitrage
Verify resolution criteria before trading. Events linked across platforms may resolve differently - settlement source, cutoff time, and tie-breakers can vary. Click any event to read each platform's rulebook.
Arbitrage
Use our live arbitrage scanner to find arbitrage between Polymarket, Kalshi and more. Get real-time results for market pricing gaps, allowing for platform fees, liquidity and timing in the profit calculation. Use the filters to set your minimum profit, ROI and APY to tailor for your needs, or see the top trades below.
Verify resolution criteria before trading. Events linked across platforms may resolve differently. Settlement source, cutoff time, and tie-breakers can vary. Click any event to read each platform's rulebook.Tap any event for each platform's rulebook.
By platform
Polymarket vs Kalshi arbitrage is essentially exploiting contract pricing differences between the two. The pairing for arbs is popular because Kalshi and Polymarket are the two biggest platforms in the space. As they have the deepest volume and liquidity, and the widest overlap in markets, price spreads between them tend to sit in a fairly consistent 2 to 5% range for their prediction market picks on a given event.
Worked example
Chiefs vs. Ravens: Chiefs Moneyline
Buying 'Yes' on Kalshi and 'No' on Polymarket totals $0.97 ($0.62 + $0.35). Either outcome for the game would give you $0.03, or a 3.09% return.
Automating and repeating this process, at volume, is where the returns start to add up. Traders running this kind of strategy using prediction trading tools can work toward a meaningful annualized return (APY), rather than treating each gap as a one-off trade. Read more in our Polymarket vs Kalshi arbitrage guide.
Kalshi's US-regulated, state-restricted access means its trader base (and information reflected in its prices) can differ from an open, global platform like Polymarket. Some states also can't access Kalshi (or specific markets) at all, which can leave those markets less efficiently priced simply because fewer informed traders are able to participate.
Polymarket can have deeper liquidity in categories like politics and sports, while Kalshi's regulated structure draws a different (and sometimes less overlapping) pool of traders, contributing to price gaps even in high-volume markets.
Kalshi uses volume-based, tiered percentage fees, while Polymarket's lower platform fees come with Polygon network gas costs on each transaction. Comparing the two requires factoring in both fee models rather than assuming one is simply 'cheaper.'
Kalshi settles in USD, while Polymarket settles in USDC. Converting between the two, along with the withdrawal frictions involved, can create a price gap between otherwise-equivalent contracts on each platform.
While Polymarket is a common leg in cross-platform arbitrage against Kalshi and others, Polymarket arbitrage also offers opportunities within its own markets. A few patterns worth watching for:
Sometimes a contract is priced below what the actual underlying probability would suggest (where Polymarket hasn't caught up to new information or public sentiment).
Comparing prices across Polymarket's own range of markets and contracts can surface inefficiencies in how they're priced relative to each other, not just relative to an external platform.
Markets with low trading volume can have price gaps sitting in the order book simply because too few traders have acted on them yet. Spotting these before the price corrects can offer an edge, though adding trading volume will move the price.
2¢ to 7¢
Profits from Polymarket arbitrage opportunities are typically 2¢ to 7¢ per contract. Capturing this kind of margin consistently at volume generally requires automated, high-frequency trading tools like a Polymarket arbitrage scanner.
Much of what applies to Polymarket carries over to Kalshi arbitrage. You can expect to find undervalued contracts, spread inefficiencies, and thin-liquidity gaps within Kalshi's range of markets. Kalshi's structure as a CFTC-regulated exchange also creates arbitrage opportunities with platforms that trade in global markets (which can price differently, or use different currencies and conversion rates).
As with Polymarket, most Kalshi arbitrage opportunities still come down to a handful of cents per contract once fees are factored in, and capturing price gaps at scale is generally a job for automated tools like a Kalshi arbitrage calculator, rather than manual monitoring.
Calculator
Use our prediction market arbitrage calculator to easily find out your return on investment (ROI) on your arbitrage trading. You can also scale that over time to see the longer term annual percentage yield (APY). Filter the available live trades by setting your minimum ROI and APY percentages.
Multi-outcome markets
A negative risk market on Polymarket links positions across all outcomes of a multi-outcome market (like elections or awards shows where there's more than two contenders, though only one eventual winner), so that betting against one outcome is economically equivalent to betting for all the others. This is also a form of prediction arbitrage, as price mismatches can mean the sum of 'Yes' prices across every outcome don't equal $1.
For example, in a multi-nominee market like Best Picture, a trader might buy 'Yes' on the frontrunner nominee, then offset that position with smaller 'Yes' bets spread across two or three of the next most likely nominees. Multi-nominee award markets often have enough contracts that the sum of 'Yes' prices across all nominees drifts from totaling $1, especially closer to the ceremony as sentiment shifts, creating room for this kind of hedge.
Done correctly, this balances exposure across outcomes in a way that can lock in a profit regardless of which specific nominee wins, similar in principle to the cross-platform arbitrage described earlier, but executed entirely within Polymarket's own market structure.
The basics
Arbitrage in prediction markets is essentially exploiting a mismatch of pricing between two prediction platforms (say, Kalshi and Polymarket) on the same event. Arbitrage happens when the combined cost of buying 'Yes' on one platform and 'No' on the other is less than $1. As all winning outcomes resolve at $1, you make a profit on the difference whatever the event outcome. This is sometimes called Dutch book arbitrage.
As an example, let's look at a market on whether Democrats will win Alaska's House seat.
Worked example
Will Democrats win Alaska's House seat?
Buying one contract of each costs 97¢ in total (4¢ + 93¢). Since exactly one side is guaranteed to resolve at $1, you lock in a 3¢ profit (though the true profit would be affected by factors like fees and price slippage, which we discuss below).
Prediction market pricing on events should total $1 between two contracts (usually yes and no). An example pricing would be 'Yes' at 96¢ and 'No' at 4¢. However, various factors can lead to a gap in these prices between different platforms (or different contract types on the same platform):
Platforms or specific markets with fewer active traders tend to have less stable pricing and lower liquidity. If Polymarket has significantly more depth (money traded) on a particular event than Kalshi, prices between the two platforms can diverge by several percentage points.
Prediction market platforms don't all reprice at the same speed when new information breaks (whether a lineup change, breaking news, or a shift in polling data). Platforms with more active traders or automated market-making typically adjust within seconds, while other platforms can take minutes to catch up. This is often where the widest (though short-lived) prediction market arbitrage gaps appear.
Even markets with generally good liquidity can thin out temporarily. This could be overnight in a platform's dominant trading time zone, or during lulls between major news cycles. With fewer active traders watching a market at certain times, a pricing gap that would normally get arbitraged away within minutes in peak hours can sit open for longer.
Where platforms have different pricing models, there will be an uneven overall 'cost' between platforms on the same event. For example, if Kalshi is priced at 4¢ 'Yes' and Polymarket at 93¢ 'No,' the raw arbitrage margin is 3¢ per contract pair. But if one platform charges a 2% fee on the trade value, that alone could consume 1-2¢ of the margin. A worthwhile arbitrage calculator factors these fees into its profit forecasts rather than comparing raw contract prices alone.
Mechanics
Prediction market arbitrage relies on spotting price gaps before the market corrects them, then moving fast enough to lock in a profit on both sides. Here's how it works in practice, from finding a genuine price mismatch through to executing it. You can also read more in our guide on checking for arbitrage.
The starting point is comparing prices for the same event across platforms, typically by having Kalshi, Polymarket, and other prediction apps open in separate tabs to check 'Yes' and 'No' prices side by side. This sounds simple but has a few practical snags:
Once you've found a genuine price gap, the next step is working out whether it's actually worth trading. A raw price difference between two platforms isn't automatically a tradable gap. You need to account for:
A gap that looks like a solid 3¢ margin on paper can shrink to near-zero or even become negative once fees, slippage, and capital costs are properly factored in.
Because so many traders, arbitrage tools, and automated systems are actively scanning for price discrepancies, trades taken against a mispricing tend to correct it to a combined price of $1 fast. This is known as the market converging.
Genuine arbitrage windows can close within seconds or minutes of appearing, which is why speed is so important with prediction market arbs. The two trades need to happen as close to simultaneously as possible. Executing manually means having both trades fully prepared and ready to submit before you place either one. You should have the contract selected, size entered, and the order pulled up on both platforms.
There's also the risk of a partial fill. Getting 60 of 100 contracts on one leg when the other has filled leaves you with a mismatched and partially hedged position. Market orders fill faster than limit orders but carry more slippage risk (as you're accepting whatever price is available, rather than one you've set). Limit orders protect your price but might not fill if the market moves before someone takes the other side.
These mechanics are exactly why executing manually is hard, and people struggle to keep pace with how quickly genuine arbitrage windows close. Many users will opt for prediction market arbitrage scanners and bots instead.
Dedicated arbitrage tools like our arb engine avoid you having to manually cross-reference prices across multiple platforms, account for fees, and execute two trades simultaneously at market speed. A tool built for this can scan multiple platforms continuously, calculate fee-adjusted margins automatically, and flag or execute opportunities far faster than a manual process. This is often the difference between capturing a gap and watching it close before you can act.
Automation
Yes, prediction market arbitrage bots are able to pull feeds from the main prediction market apps to show live events with price gaps on easy to navigate dashboards. They also normalize prices into a comparable format. This avoids the need to check platforms manually, as these tools will standardize the phrasing of contracts on different apps to match them with real world events.
A good Kalshi or Polymarket arbitrage bot will also factor in fees, slippage, and other risks to show the actual live profit calculation, rather than just the price gap between markets.
If you're looking to try or build a bot yourself, consider our v2 API, which will give you cross platform arbitrage alerts across Kalshi, Polymarket, PredictIt, ProphetX and others, as well as expected value, smart money, and other price flows. Read more on our guide to the best prediction market APIs.
Before you trade
Arbitrage is often described as 'risk-free,' but be aware that several things can limit or remove your profit from these trades.
Finally, genuine arbitrage windows tend to be short. Markets correct quickly once other traders spot the same gap, so delays anywhere in the process can mean the opportunity closes before you finish acting on it. Always bear this in mind when you trade, and budget for what you can afford to risk.
FAQ
Prediction market arbitrage means exploiting a price mismatch between two platforms (or contracts) on the same event. When buying "Yes" on one platform and "No" on the other costs less than $1 combined, you lock in a profit regardless of the outcome, since the winning side always resolves at $1.
Yes, this is one of the most popular arbitrage pairings, since both are the largest platforms by volume and liquidity, with a wide overlap in shared markets. You can take opposing positions on a market they both offer when their combined prices are below $1.00.
A prediction arbitrage scanner is a tool that continuously monitors multiple prediction apps to identify price differences for the same event. It flags live price gaps and calculates fee-adjusted profit, removing the need to manually cross-reference platforms yourself.
Negative-risk markets are Polymarket's mechanism for multi-outcome events with only one winner. They link positions across all outcomes, so betting against one is economically equivalent to betting for the rest.
You can identify mispricings in multi-outcome events where the sum of all mutually exclusive outcomes falls below $1.00.
It means the combined price of 'Yes' and 'No' contracts on the same event totals less than $1. It's the mispricing that makes arbitrage possible. Since exactly one side always resolves at $1, buying both sides for under $1 combined guarantees a profit regardless of outcome.
Not entirely. While prediction arbitrage aims to hedge positions and guarantee a fixed percentage, risks to profit can include mismatched resolution criteria, thin liquidity, fees, slippage, and execution timing.
