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    April 202610 min read

    Kalshi vs Polymarket: Are These the Same Contract?

    The same event often trades on Kalshi and Polymarket at different prices. Here's what those differences actually mean — wording, resolution source, and payout scope explained.

    Pairs Analyzed

    15+

    Platforms

    3

    Updated

    Apr 2026

    Type

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    Quick Summary

    The key takeaway from this page

    The same event often trades at different prices on Kalshi and Polymarket — but that doesn't mean one is wrong. Different contract wording, resolution sources, and payout structures explain most price gaps.
    30-second parity check

    Parity Triage Checklist

    Same event ≠ same contract. Check the rule, source, timing, fees, and fillability before treating a cross-platform spread as comparable.

    1

    Question wording

    Does the market ask the same thing?

    Pass: Wording is identical or equivalent
    Fail: Wording differs — scope may differ
    Check field: contractWording
    2

    Outcome trigger

    Is the trigger type the same (announcement, close, final reading)?

    Pass: Triggers match
    Fail: Different trigger types — may resolve differently
    Check field: resolutionTiming
    3

    Resolution source

    Is the exact source the same?

    Pass: Same source
    Fail: Different source — outcome data may differ
    Check field: resolutionSource
    4

    Resolution timing

    Do deadlines, time zones, and determination windows match?

    Pass: Timing aligns
    Fail: Timing differs — check details
    Check field: resolutionTiming
    5

    Edge-case clause

    Are fallback clauses (DNP, cancellation, ambiguous)?

    Pass: Clauses match
    Fail: Edge-case handling differs
    Check field: scopeNote
    6

    Fee + spread drag

    After fees and slippage, is there still a gap?

    Pass: Tradeable arbitrage exists
    Fail: Fees eliminate gap
    Check field: equivalenceNote
    7

    Fillability

    Can both legs fill without moving the book?

    Pass: Both sides fillable
    Fail: Liquidity constraints exist
    Check field: equivalenceNote

    Classify the spread before you trade it

    A visible gap is only useful after you know which bucket it belongs in.

    green

    Likely equivalent

    Contracts appear identical in wording and resolution

    Continue checking fees and fillability before treating the gap as comparable

    yellow

    Same headline, different mechanics

    Same event but different resolution or timing

    Review resolution details before trading

    red

    Different contract

    Different question or source — not comparable

    Do not treat as arbitrage

    unknown

    Unknown — inspect source

    Insufficient info to classify

    Fetch live rules and verify fields

    Official source-field map

    Use primary rules, help-center docs, or API docs — not screenshots — to compare contract fields.

    PlatformFieldWhere to find itPrimary sourceStatus
    kalshiresolutionSourceMarket rules page (Official documentation)Official docs
    needs verification
    kalshiresolutionTimingMarket rules page — check close and determination windowsOfficial docs
    needs verification
    polymarketresolutionSourceResolution section on event docsOfficial docs
    needs verification
    polymarketcontractWordingOfficial event API metadataOfficial docs
    needs verification
    robinhoodcontractWordingInspect underlying contract rules on GUIPrimary source needed
    needs verification

    Federal Reserve rate cut contract wording

    economics

    Scope Differs
    Do not assume two Fed markets are equivalent just because both mention the same meeting. Contract wording controls.

    Kalshi

    Contract Wording

    Example: any-cut wording on a Fed meeting contract
    Resolution Source: FOMC official statement, if specified in the contract rules
    Resolution Timing: Per the market rules and official source publication
    Scope Note: Some contracts ask whether any cut happens by a date; others ask about a specific target range or exact outcome.
    Key Difference: The threshold and timing language on the live contract page determine whether this matches another venue.

    Polymarket

    Contract Wording

    Example: exact-threshold or exact-meeting wording on a Fed contract
    Resolution Source: FOMC official statement, if specified in the contract rules
    Resolution Timing: Per the market rules and official source publication
    Scope Note: Polymarket contracts can be narrower or broader than a regulated-exchange contract depending on the exact text.
    Key Difference: The live market rules—not the headline—determine whether two contracts are actually comparable.

    Bitcoin reaches $100,000

    crypto

    Scope Differs
    Kalshi uses CF Benchmarks RTI (60-second rolling average). Polymarket uses Binance 1-minute candle High. Both can resolve on brief spikes — but the data source, exchange, and measurement methodology differ. These are meaningfully different price references.

    Kalshi

    Contract Wording

    Will BTC close above $100,000 on [date]?
    Resolution Source: CF Benchmarks Real-Time Index (CFB RTI) — 60-second rolling average of BTC price across constituent exchanges
    Resolution Timing: Settled using 60-second average at contract expiry (not a single exchange's close price)
    Scope Note: CFB RTI-based: resolves on a 60-second average, not a spot price snapshot. A brief spike may or may not cross the threshold depending on the average.
    Key Difference: CF Benchmarks RTI (60s average) — not Coinbase spot. Verified: help.kalshi.com/en/articles/13823838-crypto-markets

    Polymarket

    Contract Wording

    Will BTC reach $100,000 by [date]?
    Resolution Source: Binance BTC/USDT 1-minute candle High prices — resolves YES if any 1-minute candle High equals or exceeds the threshold
    Resolution Timing: Any 1-minute candle within the specified window
    Scope Note: Touch-based on Binance 1m High: a single candle with a High at or above $100K resolves YES, even if BTC immediately drops back.
    Key Difference: Binance BTC/USDT 1-minute candle High — not CoinGecko. Verified: polymarket.com/event/what-price-will-bitcoin-hit-in-march-2026

    NYC temperature threshold contracts

    weather

    Scope Differs
    Station and source matter more than the city label. Two NYC contracts can still be different bets.

    Kalshi

    Contract Wording

    Will NYC reach a stated temperature threshold on a stated date?
    Resolution Source: Named source agency and station listed in the market rules
    Resolution Timing: After the source publishes the relevant observation and the market is determined
    Scope Note: The exact station named in the rules governs, not a general city weather app reading.
    Key Difference: Official source + station choice can make this materially different from another venue.

    Polymarket

    Contract Wording

    Will NYC max temperature exceed a stated threshold on a stated date?
    Resolution Source: Named weather source and station listed on the market page
    Resolution Timing: After the named source finalizes the relevant reading
    Scope Note: A different station or weather vendor can produce a different outcome from a nearby official station.
    Key Difference: Different station/source selections are the real source of divergence, not just wording style.

    Super Bowl LXI — 2027

    sports

    Same Contract
    These ARE the same bet. Any spread between Kalshi and Polymarket on this market is a liquidity or timing difference — and is the closest thing to a real arbitrage opportunity on this list.

    Kalshi

    Contract Wording

    Will [Team] win Super Bowl LXI?
    Resolution Source: NFL official game result
    Resolution Timing: Night of the game (final score confirmed)
    Scope Note: Binary per team — exactly one team resolves YES
    Key Difference: No meaningful scope difference from Polymarket

    Polymarket

    Contract Wording

    Will [Team] win the Super Bowl in 2027?
    Resolution Source: NFL official game result
    Resolution Timing: Night of the game (final score confirmed)
    Scope Note: Binary per team — same structure as Kalshi
    Key Difference: No meaningful scope difference from Kalshi — price gap = liquidity or timing, not risk

    US tariff pause — 2026

    politics

    Different Contracts
    Announcement and implementation are two different events. Kalshi YES can fire while Polymarket is still open — or vice versa if a deal falls apart between announcement and implementation.
    ⚠️ SCOPE ALERT: These are NOT the same contract

    Kalshi

    Contract Wording

    Will the US announce a tariff pause on [country] by [date]?
    Resolution Source: White House official announcement / press release / Federal Register filing
    Resolution Timing: Same day as official announcement
    Scope Note: Resolves on ANNOUNCEMENT — implementation delay does not affect resolution
    Key Difference: Announcement-based: resolves YES the moment a deal is announced, even if tariffs don't change for weeks

    Polymarket

    Contract Wording

    Will US tariffs on [country] be paused by [date]?
    Resolution Source: Federal Register / US Trade Representative effective date notice
    Resolution Timing: On effective date — when tariffs are actually paused
    Scope Note: Resolves on EFFECTIVE date — announcement does not resolve YES
    Key Difference: Effective-date-based: an announcement alone doesn't count — the tariffs must actually change

    How to Read Contract Differences

    Three dimensions explain almost every cross-platform price gap.

    Wording Differences

    Prediction markets are legal contracts. Every word in the title changes what the contract covers. 'Will X happen?' and 'Will X happen by [specific date] via [specific mechanism]?' are fundamentally different questions — and different settlement triggers.

    Example

    "Will the Fed cut rates?" captures any cut of any size at any meeting. "Will the Fed cut 25bp at the June 19 meeting?" captures exactly one scenario. A 50bp cut on June 19 resolves the first YES and the second NO.

    Resolution Source

    Two contracts on the same event can use different data sources — and those sources can disagree. Official government data (NOAA, BLS, FOMC statements) tends to be more conservative and slower to update than consumer-facing data (Weather.com, CoinGecko).

    Example

    On a 95°F day in NYC, NOAA's official Central Park ASOS station might read 93.8°F (shaded, standardized placement). Weather.com might show 96°F. One contract resolves YES; the other NO — on the exact same day.

    Payout Scope

    Scope changes the implied probability of YES. A broader question ('any cut, any size') will almost always be priced higher than a narrower question ('exactly 25bp cut'). This is not a mispricing — it is the market correctly pricing two different outcomes.

    Example

    If the Fed has a 70% chance of cutting at all, and a 50% chance of cutting by exactly 25bp (rather than 50bp), a 'any cut' contract should trade near 70¢ and a '25bp exactly' contract near 50¢. The 20¢ gap is not arbitrage — it reflects real probability difference.

    When a Spread Is NOT Arbitrage

    Most cross-platform price gaps have a structural explanation. Four common reasons:

    Different scope

    Kalshi: any cut, any size. Polymarket: specifically 25bp. A 50bp surprise resolves YES on Kalshi, NO on Polymarket.

    Different deadline

    One contract expires March 31; the other April 30. Same event, different windows — both can be YES or NO independently.

    Different resolution source

    NOAA ASOS official station vs Weather.com reading. Same hot day, 2°F difference, one resolves YES, one resolves NO.

    Actual arbitrage

    Real — but closes within seconds to minutes on liquid markets. If you see it, it is almost certainly already gone.

    → View live arbitrage opportunities→ Settlement rules comparison

    How Contract Structure Varies by Exchange

    Platform-specific contract mechanics

    Kalshi

    Binary event contracts on a central limit order book. Contracts pay $1 or $0. Resolution uses official data sources (BLS, NOAA, AP). Broadest category coverage — 9+ categories including weather, science, and entertainment. Fee: trading fee (charged when you buy at market price) — many markets are free.

    In plain English: Kalshi's fee varies by odds — max 1.75¢/contract at 50/50. Near-certainties and longshots cost almost nothing.

    Polymarket

    Binary outcome tokens on Polygon blockchain. Trades via CLOB (Conditional Token Framework). US version resolves via centralized Markets Team under CFTC oversight; international version uses UMA optimistic oracle with on-chain dispute. USDC-denominated.

    ForecastEx (Interactive Brokers)

    CFTC DCM + DCO. Binary contracts integrated into IBKR's institutional trading platform. Covers economics, politics, and finance — no sports. Contracts trade alongside stocks, options, and futures in the same IBKR account. Resolution uses official government and financial data sources.

    Even when two exchanges list the same event, contract wording, resolution sources, and settlement timing may differ. Always read the full contract specification before assuming cross-platform prices are comparable.

    Frequently Asked Questions

    8 common questions answered

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