KALSHI Trading Fees Explained for Arbitrage Traders
Kalshi trading fees are a key factor in any arbitrage calculation on the Kalshi platform. Kalshi charges a per-contract fee on each filled order, applying to both sides of a binary YES/NO market. The effective cost is driven by the contract price and the total number of contracts you trade, which means edge strategies that rely on tight spreads must account for these costs. While the fee structure is straightforward in principle, understanding how it scales with your position and how to optimize around it is essential for sustained profitability.
How Kalshi fees are charged on each trade
Kalshi applies a per-contract fee to every filled order. The fee scales with the price and the quantity traded, and there is no maker rebate in standard markets. In practical terms, buying YES or NO at a mid-price of around 0.50 (50¢) incurs a higher per-contract fee than trading at the extremes, since the fee approximates a function of P and (1−P). This means your total cost for a two-leg arbitrage can be close to the sum of the two per-contract fees, reducing the guaranteed edge if the spreads are not wide enough. Always factor the fee into your breakeven calculations when assessing edge size and expected payoff.
How fees impact intra-market and combinatorial arbitrage
Intra-market arbitrage relies on a gap where YES_ask plus NO_ask is less than $1.00. The Kalshi fee reduces the net edge you can lock in, especially for small-priced contracts near the extremes. Combinatorial arbitrage across mutually exclusive child markets under the same event ticker also pays fees on each leg. Even when you secure a risk-defined spread, the aggregate per-contract fees across all child contracts should be included in your profitability model. The key is to ensure the gross edge exceeds the total fees by a comfortable margin.
Strategies to manage and minimize fees
To minimize fee impact, target markets where your total workload yields a larger edge relative to the cost. Favor edges where the sum of YES and NO prices is well below $1.00 so that the gross edge is significant before fees. Consider batching orders where possible and use post-only or IOC flags if the platform supports them to avoid unwanted fills. Remember that the fee is per contract, so increasing contract count only makes sense if it increases the net edge after fees.
Start optimizing Kalshi trades with KalshiArb
Unlock edge-ready Kalshi opportunities with KalshiArb. Our alerts and tooling help you account for fees and maximize the net edge on YES/NO contracts.
FAQ
- What is Kalshi's trading fee on a typical market?
- Kalshi charges a per-contract trading fee on each filled order. The exact amount depends on the contract price and the number of contracts traded; the fee is designed to be smallest at the price extremes and larger near $0.50.
- Do YES and NO sides incur the same fee?
- Yes. The fee structure applies to both YES and NO sides symmetrically, and both sides contribute to the total per-contract cost in a given trade.
- Are there any fee waivers or specials I should know about?
- Kalshi sometimes runs fee waivers on select high-volume markets, but these are not guaranteed and are flagged in the API responses. For typical markets, treat the standard per-contract fee as the baseline.
- How do fees affect large multi-leg arb like combinatorial sets?
- Fees accrue on every leg of the trade, so multi-leg arb increases total fees. Ensure the aggregate edge across all legs remains positive after accounting for fees and slippage, especially in slower-moving markets.