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Fees and Tax

KALSHI Fees vs POLYMARKET: What Traders Should Know

kalshi fees vs polymarket is a common question for traders weighing cost and edge on two major event markets. This article breaks down how Kalshi’s USD-settled, CFTC-regulated design contrasts with Polymarket’s crypto-settled model, and what that means for your arbitrage work. You’ll see how Kalshi’s per-contract fee curve interacts with mid-price edges, and why the cost of both sides on a binary can matter for real money opportunities. The goal is to help you quantify edge rather than chase vague promises of ‘cheapest fees.’

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Understanding Kalshi’s fee structure vs general market fees

Kalshi charges a trading fee on each order that applies to both maker and taker activity. The fee is calculated per fill and scales with price and size, with the typical effect that contracts priced near $0.50 incur a higher per-contract fee than those at the extremes. There are no maker rebates on standard markets, so both sides of a trade contribute to the fee. Kalshi’s rules also cap the contract payoff at $1.00, which means you’re always paying a percentage of a binary’s price rather than an opaque premium on a settlement. In practice, this means you should evaluate your total cost by looking at the price you pay for each YES and for each NO, then sum them to estimate edge after fees.

Polymarket’s model vs Kalshi’s: crypto rails and regulatory framing

Polymarket operates with crypto rails and crypto settlement, which leads to a different fee and risk profile than Kalshi’s USD-settled design. Because Polymarket is crypto-based, fee structures can depend on the underlying chain economics, tokenomics, and exchange-specific costs. KalshiArb focuses on intra-market edge opportunities within Kalshi’s binary structure, where the sum of best-ask YES and best-ask NO tends to reveal arbitrage opportunities when it dips below $1.00. For a US-based trader, the regulatory and settlement framework on Kalshi is distinct from crypto-native platforms, which affects cost transparency and execution risk.

Practical implications for intra-market arbitrage

If bestAsk(YES) + bestAsk(NO) is less than $1.00, you can buy both legs and lock a risk-defined edge after fees. The exact edge depends on the contract price, the number of contracts traded, and the brokerage-like fees Kalshi charges per fill. Because there is no free lunch, you must subtract Kalshi’s fee curve from your gross spread to determine real profitability. Kalshi’s edge logic also extends to combinatorial spreads across child markets under the same event ticker, where the sum of YES prices across children can reveal a larger guaranteed edge when the market structure allows it.

Managing costs with KalshiArb pricing and tools

KalshiArb provides non-custodial tooling to monitor price edges and alert you to favorable conditions. Since fees are embedded in the trade, real-time edge calculation helps you decide when to place both legs and when to hold off. The product emphasizes sub-100ms reaction times and accurate price tracking across the Kalshi REST and WebSocket feeds so you can quantify the net edge after the per-contract fee. Pricing plans place emphasis on alerting versus execution, with a focus on helping you identify actionable Kalshi-to-Polymarket comparisons within Kalshi’s USD-settled framework.

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FAQ

How should I compare kalshi fees vs polymarket in practice?
Focus on edge after fees within Kalshi. Kalshi’s per-contract fee applies to each fill, and the YES/NO prices must sum to $1.00 for fair value. Polymarket’s costs come from its crypto rails and token-allocated fees, which differ from Kalshi’s USD settlement. The practical takeaway is to measure your gross spread against Kalshi’s fee curve to estimate net profitability.
Are there maker rebates or rebates for Kalshi trades?
Kalshi does not offer maker rebates on standard markets. The fee applies to both makers and takers. Some high-volume, temporary market subsets may waive fees, and those will be flagged in the API response.
Can I rely on a single price edge to guarantee profit on Kalshi?
No. Even with a favorable edge where YES_ask + NO_ask < $1.00, you face slippage, partial fills, and the Kalshi fee curve. Edge confidence comes from rapid execution, accurate price data, and accounting for fees across both legs and any combinatorial markets you’re trading.
What should US-based traders know about regulation when comparing these platforms?
Kalshi is a U.S.-based, CFTC-regulated DCM with USD settlement. Polymarket operates as a crypto-native platform with different regulatory and settlement considerations. For traders prioritizing regulatory clarity and USD settlement, Kalshi is the compliant option, while Polymarket represents a different risk/structure.

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