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 |
|---|---|---|---|---|---|---|---|
| Sports | 96% | 89% | 79% | 68% | 61% | 79% | Always cheaper |
| Politics | 94% | 86% | 71% | 57% | 49% | 71% | Always cheaper |
| Other | 97% | 87% | 64% | 60% | 77% | 71% | Always cheaper |
| Tech | 94% | 86% | 71% | 57% | 49% | 71% | Always cheaper |
| Culture | 93% | 82% | 64% | 46% | 36% | 64% | Always cheaper |
| Mentions | 97% | 83% | 55% | 50% | 71% | 64% | Always cheaper |
| Weather | 88% | 79% | 64% | 38% | -7% | 58% | Flips above 89c |
| Economics | 86% | 75% | 57% | 26% | -29% | 50% | Flips above 85c |
| Crypto | 90% | 74% | 49% | 23% | 7% | 49% | Flips above 98c |
| Finance | 89% | 71% | 43% | 14% | -3% | 43% | Flips above 88c |
Positive % = Polymarket cheaper. Negative = Kalshi cheaper. Avg is weighted across 5c–95c.
Fee Formulas
Polymarket
10 category-specific schedules
fee = C × p × feeRate × (p × (1-p))^expC = contracts, p = share price. Makers earn a 20-50% 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.
Key Insights
Polymarket is cheaper across all categories
In absolute dollar terms, Polymarket charges lower taker fees than Kalshi in every market category. The average savings at 50c is 63%, ranging from 43% (Finance) to 79% (Sports). Each platform reports "peak rates" using different denominators — comparing them directly is misleading.
Low-price contracts are nearly free on Polymarket
Polymarket's formula includes a × p factor that makes fees vanish at low prices. At 10c, savings are 86–97% vs Kalshi. This rewards buying cheap longshots and encourages price discovery at the tails.
Makers earn on Polymarket, pay on Kalshi
Polymarket pays makers a 20–50% 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.
Exponent matters more than fee rate
Sports and Economics share the same 0.03 fee rate, but Sports (exp 1) costs $0.38 at 50c while Economics (exp 0.5) costs $0.75 — nearly 2×. Lower exponents widen the fee curve. Higher exponents (like 2 for Other/Mentions) crush fees at price extremes.
Higher fees at extremes discourage volume farming
In 4 categories (Economics, Finance, Weather, Crypto), Polymarket fees exceed Kalshi above 85–98c. This disincentivizes wash trading on heavy favorites — the typical volume farming strategy of churning at 95c+ becomes costly. For genuine traders, this rarely matters. Sports, Politics, Tech, Culture, Other, and Mentions never flip.
Platform Comparison
Polymarket
- •10 category-specific fee schedules
- •Variable exponents change curve shape
- •Makers earn 20–50% 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.