Arbitrage Calculator

Enter YES and NO prices for the same event across Polymarket and Kalshi.

YES price (e.g. Polymarket)

NO price (e.g. Kalshi)

Total cost (YES + NO)$0.9600

Gross spread4.00%

Net edge after fees1.02%

Profit per $100 invested+$1.02

✅ Arbitrage opportunity — 1.02% net edge

Arbitrage Agent finds matching pairs and shows them in a live feed with a step-by-step guide. You place the orders yourself.

Reads the YES price as the Polymarket leg and the NO price as the Kalshi leg. Polymarket taker fee = 0.05 × price × (1 − price) per contract (0.05 is the rate for most categories — politics and finance pay 0.04, crypto 0.07, geopolitics 0; the calculator does not know the category). Kalshi taker fee = 0.07 × price × (1 − price), before rounding up to the cent and without any market-specific changes. Net edge only — actual profit depends on fill prices and slippage. Not financial advice.

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How to use this calculator

Enter the best ask price for the YES side on one platform (e.g. Polymarket) and the best ask price for the NO side on the other platform (e.g. Kalshi) for the same real-world event. The calculator instantly shows whether a profitable arbitrage opportunity exists after accounting for typical platform fees.

Gross spread is the raw gap between $1.00 (the guaranteed settlement value of any binary contract) and your combined cost. A positive gross spread means the market is theoretically mispriced. Net edge after fees deducts both platforms' taker fees (Polymarket at the 0.05 rate, Kalshi at 0.07) to give you the realistic profit available.

Profit per $100 shows the expected dollar return if you deploy $100 across both legs at the quoted prices. This assumes full fills at the quoted price — actual returns will vary based on order book depth and slippage.

What makes an arbitrage opportunity valid?

A valid opportunity requires that the combined cost of YES and NO for the same event across two platforms is below $1.00 after fees. On Polymarket and Kalshi, the same binary event is often priced differently because the platforms have independent liquidity pools and different user bases. These price gaps can close quickly as other traders and market makers act on them.

Net edges after fees are usually small. See the live numbers on the proof page for what the scanner actually measures. See the full arbitrage guide for more detail.

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