Compare Kalshi and Polymarket Quotes | Zobet AI
Different prices on Kalshi and Polymarket can be a useful research prompt. They are not enough to establish a profitable trade. Before interpreting a gap, check whether the contracts ask the same question and whether the numbers represent comparable prices. This guide gives you a way to document that comparison without assuming the gap is money you can collect.
Compare the rules before the numbers
Place both contract descriptions side by side. Match the event, outcome, threshold, deadline, time zone, and resolution source. Look for different treatment of revisions, cancellations, or ambiguous outcomes. Similar headlines are a reason to investigate, not proof that the contracts are equivalent.
Polymarket’s documentation says the rules define resolution, while the title describes the question. Kalshi likewise directs users to the market’s rules and determination details. If a condition differs, explain the difference in your notes before comparing prices. The mismatch might be the entire reason for the apparent gap.
Sources: Polymarket Documentation: Resolution; Kalshi Help Center: Market FAQs.
Label each price by side and purpose
Write down whether you are comparing YES or NO, and whether each number is a bid, ask, last trade, or displayed probability. Polymarket states that its displayed price generally uses the bid-ask midpoint, switching to the last trade when the spread exceeds 10 cents. That display is not a promise of an available fill.
Compare like with like. For an intended purchase, inspect the available selling prices and quantities for that outcome. For a potential sale of an existing position, inspect buying interest. Record the observation times as well, because a fresh quote and an older screenshot describe different moments.
Sources: Polymarket Help Center: How Are Prices Calculated?; Kalshi Help Center: The Orderbook.
Hypothetical example: a five-point gap
Imagine an alert shows YES at 45 cents on one venue and 50 cents on another. These are invented figures. After checking the books, you discover that the first number is a last trade, while the second is a midpoint. The lowest available selling price is 51 cents on the first venue and 52 cents on the second.
The two headline numbers differ by five cents. The observed purchase quotes differ by one cent. For ten contracts, those purchase quotes imply $5.10 versus $5.20 before fees, assuming the quantity is available. Neither comparison establishes a profit: it only describes the information you have collected.
If you considered a transaction involving both venues, you would also need to examine each required side, execution sequence, and settlement condition. Do not treat an apparent mismatch as a completed, simultaneous trade. One action succeeding while another fails would leave a different position from the one you intended.
Include costs and practical constraints
Check the current fee information for the specific markets and order types. Kalshi notes that fees can vary by market. Polymarket documents taker fees on certain markets. Avoid building a comparison around an assumption that every trade on either venue is free.
Record the quantity available at the relevant prices, the funds you can actually use on each venue, and any unresolved access or transfer issue. Refresh the quotes before making a decision. A comparison is more useful when it records its limits instead of compressing everything into a single attractive percentage.
Sources: Kalshi Help Center: Fees; Polymarket Documentation: Fees.
Keep a comparison you can revisit
Save both contract links, rule differences, outcome side, quote type, timestamp, quantity, and estimated costs. End the note with what you verified and what remains unknown. This gives you a record you can review even if you decide not to trade.
Zobet Alerts surfaces market-price comparisons for your review. It does not guarantee that contracts are interchangeable, that prices will remain available, or that a difference will produce a profitable trade. You make the trading decisions.
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