Polymarket Expected Value Calculator

Calculate EV and optimal sizing for Polymarket positions, accounting for the 2% profit fee.

PM EV CalculatorPolymarket · Crypto-Based

Why This Matters

Polymarket's fee structure is unique: the Global platform only charges 2% on net profits. This means your EV calculation only needs to account for fees on winning scenarios — losing trades are fee-free. This asymmetry favors high-conviction, lower-probability bets.

Calculator

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Step-by-Step: PM EV Calculator on Polymarket

  1. 1

    Enter the Polymarket contract price and select Polymarket.

  2. 2

    Choose Global or US region to apply the correct fee structure.

  3. 3

    Input your true probability estimate.

  4. 4

    Review the EV including fee adjustments.

  5. 5

    Check the Kelly sizing — it will account for the asymmetric fee structure.

Worked Example

Polymarket Global Yes at $0.35, true probability 45%. Fee only on winning: 2% × $0.65 = $0.013. EV = (0.45 × $0.637) - (0.55 × $0.35) = $0.287 - $0.193 = +$0.094/contract. Strong +EV with minimal fee drag.

Polymarket Fee Summary

Fee model: 2% on net profits at withdrawal (Global) / 0.1% taker fee (US)

Formula: Global: 0.02 × net profit | US: 0.001 × premium per trade

Timing: Charged at resolution or withdrawal

Pro Tips

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