Find and calculate arbitrage between Polymarket and other prediction markets. Account for Polymarket's per-category taker fee.
Polymarket's deep liquidity on political markets often creates temporary price differences with Kalshi and Robinhood. Both legs of an arb pay the per-category taker fee at trade, or $0 if you post limit orders as a maker. The arb dynamic favors Polymarket because its taker rates (0.04 on politics and finance, 0.05 on sports) sit below Kalshi's 0.07, and makers pay nothing.
Compare Polymarket contract prices with the same event on Kalshi or Robinhood.
Enter both sides' prices into the Arb Calculator.
Select the correct fee structure for each platform.
Note: Polymarket charges the taker fee on both legs at trade, or $0 if you post limit orders as a maker.
Calculate guaranteed profit and optimal stake split.
Polymarket politics Yes at $0.45. Taker fee = 0.04 × 0.45 × 0.55 = $0.0099 per share, charged at trade. Robinhood No at $0.50 (fee = $0.02). Total cost: $0.45 + $0.0099 + $0.50 + $0.02 = $0.98. Guaranteed payout: $1.00. Arb profit: $0.02/contract. Post the Polymarket leg as a maker to pay $0 and widen the margin.
Fee model: Per-category taker fee: fee = C × feeRate × p × (1−p). 0.05 sports, 0.07 crypto, 0.04 politics/finance. Makers pay 0.
Formula: C × feeRate × p × (1 - p); feeRate 0.04–0.07 by category (sports 0.05 as of Jul 2026)
Timing: Charged at time of trade
Find risk-free arbitrage opportunities between Kalshi and other prediction markets. Calculate stakes and guaranteed profit after fees.
Polymarket Fee Calculator: Per-Category Taker Fees ExplainedCalculate Polymarket's per-category taker fee (0.04–0.07 by category) with the fee = C × feeRate × p × (1−p) formula.
Polymarket Break-Even CalculatorCalculate the minimum win rate needed to profit on Polymarket after the per-category taker fee.
Polymarket Expected Value CalculatorCalculate EV and optimal sizing for Polymarket positions, accounting for the per-category taker fee.
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