The fee formula
Kalshi charges a per-contract trading fee calculated as roughly 7¢ × contracts × price × (1 − price), rounded up to the nearest cent. Translation: fees peak in the middle of the book and approach zero at the extremes. A $0.50 contract costs the most to trade; a $0.05 or $0.95 contract costs almost nothing.
Worked examples
- 100 contracts at $0.50 → 7¢ × 100 × 0.5 × 0.5 = $1.75 fee
- 100 contracts at $0.10 → 7¢ × 100 × 0.1 × 0.9 = $0.63 fee
- 100 contracts at $0.90 → 7¢ × 100 × 0.9 × 0.1 = $0.63 fee
What's NOT a fee
Kalshi does not charge deposit fees, ACH withdrawal fees, account fees, or inactivity fees. There's no spread markup added on top of the order book — what you see is what fills.
How this compares to sportsbooks
A typical −110 sportsbook line bakes in ~4.5% vig. On a 50/50 market, Kalshi's effective cost is closer to 1.75% of notional — meaningfully cheaper for breakeven traders.