Prediction markets advertise low or zero fees. The real cost of a trade is higher. Platform fees are only one component. Add network gas costs, trading fees on winning positions, and slippage from market depth, and a "$0 fee" trade actually costs 2-7% depending on the platform and trade size.
This calculator shows the full cost breakdown for any trade size across 7 prediction market platforms. Enter the amount you plan to trade, and see exactly what you'll pay on each platform. The comparison includes gas estimates based on current network conditions and slippage estimates based on typical market liquidity.
P2P Fee Calculator Tool
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How to Use the Fee Calculator
- Enter your trade size in USD. The calculator shows costs for that exact amount.
- Compare platforms side by side. Each platform shows: platform fee, trading fee, gas cost, estimated slippage, and total cost as both a dollar amount and percentage.
- Factor in what matters to you. Polymarket may be cheapest but requires a crypto wallet. Kalshi costs more but uses USD. Azuro is decentralized but has smart contract risk.
Frequently Asked Questions
What fees do prediction markets charge?
Prediction markets charge a combination of platform fees, trading fees (on winning positions), network gas costs (for blockchain-based platforms), and implicit costs from slippage on low-liquidity markets. This calculator breaks down each component so you can see the true total cost.
Does Polymarket really have 0% fees?
Polymarket charges 0% platform fee, but there is a ~2% trading fee on winning positions and Polygon network gas costs (~$0.30-0.50 per transaction). The total cost on a $100 winning trade is approximately $2.50. "0% fees" is technically true for the platform fee but misleading about total cost.
How do Kalshi fees compare to Polymarket?
Kalshi charges variable fees depending on the contract, typically 3-7% on profits. There are no gas costs since Kalshi is centralized. For most trade sizes, Polymarket is cheaper overall, but Kalshi offers CFTC regulation and USD deposits with no crypto wallet needed.
What is slippage in prediction markets?
Slippage is the difference between the quoted price and your actual execution price. On low-liquidity markets, large orders can move the price against you by 1-5%. This is effectively a hidden fee. The calculator estimates slippage based on typical market depth.
Which prediction market has the lowest total fees?
For most trade sizes, Polymarket has the lowest total cost (including gas). Azuro can be cheaper for small trades on Gnosis chain (very low gas). Kalshi is more expensive per trade but has zero crypto-related costs. The cheapest platform depends on your trade size and how you value regulatory protection.
How are gas costs estimated?
Gas costs are based on current network conditions for each platform's blockchain: Polygon for Polymarket, Polygon/Gnosis for Azuro. Estimates are updated regularly but actual gas costs fluctuate with network congestion. The calculator uses recent median gas prices.
Is this calculator free?
Yes, completely free. Enter your trade size and select platforms to compare total costs side by side.