Kalshi vs Polymarket fees, at your price

Both venues charge more when a contract is near 50¢ and almost nothing near the extremes — the fee is a curve, not a flat rate. The headline numbers ("7%" vs "6%") are the coefficients in that curve. Enter a price and a size:

The formulas, as published

• Kalshi taker: 0.07 × price × (1 − price) per contract, times a per-series multiplier that the schedule (effective July 7, 2026) sets to 1 for nearly every series and 0 for a few fee-free ones (some crypto year-end ranges and geopolitical questions). Rounded up to the cent per contract here; the venue rounds per order, so this is the conservative reading. Maker fee: 0 by default; on series where the schedule sets a maker multiplier of 1 (most sports, CPI, Fed decisions, jobs, GDP) it is 0.0175 × price × (1 − price), which is 25% of the taker rate.
• Polymarket US taker: 0.06 × price × (1 − price) per contract, per the schedule effective July 1, 2026 (maximum $1.50 per 100 contracts at 50¢). Makers are paid, not charged: a rebate of 0.0125 × price × (1 − price), up to $0.31 per 100 contracts. Large takers get volume rebates above $250,000 a month.
• Polymarket (global): takers only, at a rate by category — crypto 0.07, sports/economics/culture/weather 0.05, finance/politics/tech 0.04, geopolitics 0. Makers are never charged. Not available to US accounts.

At a glance

Both peak at 50¢: 1.75¢ (Kalshi, shown rounded up to 2¢ per contract) vs 1.5¢ (Polymarket US). At 90¢ they are 0.63¢ (rounded to 1¢) and 0.54¢. Deposits, withdrawals, and any crypto on-ramp costs are separate and not modeled here. Corrected 2026-09-04 against the current schedules: an earlier version of this page said Kalshi charged a higher multiplier on some categories and that Polymarket US charged makers; neither is what the schedules say.

Sources

• Kalshi Help Center — Fees
• Kalshi fee schedule (effective July 7, 2026, PDF)
• Polymarket US — Fee Schedule
• Polymarket (global) — Fees