Compared
Prediction market fees compared
Kalshi, Polymarket US, Gemini and Polymarket all charge rate × contracts × price × (1 − price). The rates, who pays and the rounding differ. Here they are side by side, checked October 31, 2026.
| Venue | Taker rate | Maker fee | Rounding | 100 at 50¢ |
|---|---|---|---|---|
| Kalshi | 0.07 | 0.0175 on series that charge makers | Up to the cent | $1.75 |
| Polymarket US | 0.0695 (0.10 table tennis) | None; rebates at high volume | To the cent, half to even | $1.74 |
| Gemini | 0.07 | 0.0175; $0 through Dec 31, 2026 | Up to the cent | $1.75 |
| Polymarket (international) | 0.04 to 0.07 by category; 0 on geopolitics | None | To 5 decimals | $1.00 to $1.75 |
“100 at 50¢” is the taker fee on one order of 100 contracts at 50¢, the price where fees are highest.
Which is cheapest?
- Taking a price: Polymarket US (0.0695) is a hair under Kalshi and Gemini (0.07). Polymarket’s politics, finance, tech and mentions markets (0.04) are cheaper still, and its geopolitics markets are free.
- Posting a resting order: free on Polymarket US and Polymarket, free on Gemini through 2026, and 0.0175 on Kalshi series that charge makers.
- Small orders: venues that round up to the cent charge at least 1¢ on any order with a fee, which is a lot on a 5¢ contract.
Fees on a two-sided trade
Buying both sides on two venues pays a fee on each leg. Near 50¢ that’s about 3.5¢ per pair between Kalshi, Polymarket US and Gemini, so a gap has to be bigger than that to pay. Near 10¢ or 90¢ fees are about a third as large. The arbitrage calculator works out any trade, and live odds show where the gaps are right now.
Fees decide whether a price gap pays. ArbTrader scans Kalshi, Polymarket US, Gemini and Polymarket for spreads that still pay after every venue’s fee, at the size actually for sale, and pings you when one opens.
Fee rules from each venue’s published schedule, checked October 31, 2026. Venues change fees; check the venue’s own fee page before trading. Not financial advice. ArbTrader isn’t affiliated with any venue named here.
Common questions
Which prediction market has the lowest fees?
For takers, Polymarket US at 0.0695 is slightly below Kalshi and Gemini at 0.07, and Polymarket charges 0.04 on politics, finance, tech and mentions markets. For makers, Polymarket US and Polymarket charge nothing, and Gemini charges nothing through December 31, 2026.
Why are prediction market fees highest at 50 cents?
The formula multiplies price by (1 minus price), which peaks at 50 cents. A contract near 50 cents carries the most uncertainty, so it costs the most to trade.
Do Kalshi, Polymarket US or Gemini charge a fee when a contract settles?
No. Each charges its trading fee when the order fills; a winning contract pays the full $1.