Fee Comparison
A side-by-side analysis of trading fees on Polymarket's new schedule vs Kalshi across all market categories.
Fee at 50c per 100 Shares
Dollar fee for 100 shares at 50c — the highest-fee price point. Apples-to-apples comparison across platforms.
sorted
by diff.
Fee Explorer
Dollar fees across contract prices for a given Polymarket category vs Kalshi.
Savings Breakdown
Polymarket savings vs Kalshi by category at key price points (per 100 shares). Sorted by average savings across all prices.
| Category | 10c | 25c | 50c | 75c | 90c | Avg | Note |
|---|---|---|---|---|---|---|---|
| Geopolitics | 100% | 100% | 100% | 100% | 100% | 100% | Always cheaper |
| Sports | 57% | 57% | 57% | 57% | 57% | 57% | Always cheaper |
| Politics | 43% | 43% | 43% | 43% | 43% | 43% | Always cheaper |
| Mentions | 43% | 43% | 43% | 43% | 43% | 43% | Always cheaper |
| Tech | 43% | 43% | 43% | 43% | 43% | 43% | Always cheaper |
| Economics | 29% | 29% | 29% | 29% | 29% | 29% | Always cheaper |
| Culture | 29% | 29% | 29% | 29% | 29% | 29% | Always cheaper |
| Weather | 29% | 29% | 29% | 29% | 29% | 29% | Always cheaper |
| Other | 29% | 29% | 29% | 29% | 29% | 29% | Always cheaper |
| Crypto | -3% | -3% | -3% | -3% | -3% | -3% | Flips above 1c |
| Finance | -14% | -14% | -14% | -14% | -14% | -14% | Flips above 1c |
Positive % = Polymarket cheaper. Negative = Kalshi cheaper. Avg is weighted across 5c–95c.
Fee Formulas
Polymarket
5 category-specific rate tiers
fee = C × feeRate × p × (1-p)v2: fee = C × feeRate × (p×(1-p))^exp
v1: fee = C × p × feeRate × (p×(1-p))^exp
C = contracts, p = share price. Makers earn a 20-25% rebate on fees from filled resting orders.
Kalshi
Flat rate, rounded up to next cent
fee = roundUp(rate × C × P × (1-P))Taker 7%, Maker 1.75%, S&P/NASDAQ 3.5%. No settlement or membership fees.
Formula Evolution
How Polymarket's fee formula changed across versions — dollar fees at each price point.
v1 and v2 use the original category parameters (rate & exponent). Current uses the new simplified rates. For categories that had exponent=1 and unchanged rates, v2 and Current overlap — try Economics, Weather, Other, or Mentions to see the biggest differences.
Key Insights
Polymarket is cheaper across all categories
In absolute dollar terms, Polymarket charges lower taker fees than Kalshi in every non-free market category. Both platforms now use the same p×(1-p) curve shape — Polymarket simply uses lower rates. Geopolitics markets are entirely fee-free on Polymarket.
Formulas now match in structure
With the exponent removed, Polymarket and Kalshi now use the exact same formula: rate × C × p × (1-p). The only difference is the rate itself. This makes comparison straightforward — Polymarket is cheaper whenever its category rate is below Kalshi's 7%.
Makers earn on Polymarket, pay on Kalshi
Polymarket pays makers a 20–25% rebate on fees from filled resting orders — you're rewarded for providing liquidity. Kalshi charges makers a 1.75% fee with no rebate. For active market makers, this is a fundamental difference.
Simplified from 10 unique curves to 5 rate tiers
The original schedule had 10 categories with different exponents (0.5, 1, 2) creating wildly different curve shapes. Now there are just 5 rate tiers: 7.2% (Crypto), 3% (Sports), 4% (Finance/Politics/Mentions/Tech), 5% (Economics/Culture/Weather/Other), and 0% (Geopolitics).
Categories like Mentions and Other got much cheaper
Under v2, Mentions (rate 0.25, exp 2) and Other (rate 0.2, exp 2) had steep fees near 50c but nearly zero at extremes. Now they use flat 4% and 5% rates respectively — dramatically cheaper at mid-range prices, slightly more at price extremes.
Platform Comparison
Polymarket
- •5 rate tiers across 11 categories
- •Same p×(1-p) curve as Kalshi, lower rates
- •Makers earn 20–25% rebate on filled resting orders
- •Fees in shares (buy) or USDC (sell)
- •Referral program: 30% direct / 10% indirect
- •No deposit/withdrawal fees (crypto native)
Kalshi
- •Flat 7% fee-rate for all categories (taker)
- •Reduced 3.5% for S&P 500 & NASDAQ-100
- •Makers charged 1.75% fee (no rebate)
- •Fees rounded up to the next cent
- •No settlement or membership fees
- •Free ACH; max 2% on debit deposits
Note: Each platform reports "peak rates" differently — Polymarket as fee ÷ position cost, Kalshi as fee ÷ max payout. These are not directly comparable. The dollar fee comparison above uses the same metric for both. In absolute dollar terms, Polymarket is cheaper across all categories.
Sources
Polymarket announced a new category-based fee structure effective March 30, 2026. Kalshi's schedule was last updated February 5, 2026. The data above is sourced directly from official documentation.