Fees directly impact your prediction market profits. A winning trade can still lose money if the costs are too high. Here's a detailed breakdown of how Kalshi and Polymarket fees compare in 2026, so you can choose the platform that costs you less.
Kalshi fee structure
Kalshi is a CFTC-regulated exchange that operates on a traditional order book model. Here's what you pay:
- Trading fee: Kalshi charges a per-contract fee on each trade. The fee depends on contract price and whether you're a maker or taker.
- Maker fee: Lower fee when you place limit orders that add liquidity to the order book.
- Taker fee: Higher fee when you place market orders that remove liquidity.
- Settlement fee: Small fee when a contract resolves and pays out.
- Deposits: Free via bank transfer (ACH). Instant deposits may have a fee.
- Withdrawals: Free for standard ACH withdrawals. Wire transfers may incur a fee.
Typical cost per trade: Approximately 1-7¢ per contract depending on the price and order type. Lower-priced contracts have lower absolute fees.
Polymarket fee structure
Polymarket operates on Polygon (an Ethereum Layer 2) using USDC. The fee model is different:
- Trading fee: Polymarket charges a small percentage on trades. Maker orders (limit orders) are often free or heavily discounted.
- Maker fee: Typically 0% — placing limit orders that add liquidity is free.
- Taker fee: Small fee when taking liquidity from the order book.
- Settlement fee: No explicit settlement fee, but winning shares resolve to $1.
- Gas fees: Polygon transactions cost fractions of a cent. Negligible.
- Deposits: Requires USDC on Polygon. If converting from USD, you pay exchange conversion fees externally.
- Withdrawals: No Polymarket fee. Small Polygon gas cost (usually under 1¢).
Typical cost per trade: Near-zero for makers, small percentage for takers. The crypto on-ramp/off-ramp is where hidden costs add up.
Side-by-side comparison
Here's how the costs stack up on a typical $100 trade:
- Trading fees: Polymarket is cheaper for limit orders (0% maker). Kalshi charges makers a small fee.
- Taker fees: Both platforms charge more for market orders. Costs are comparable.
- Deposit costs: Kalshi wins. Bank transfer is free. Polymarket requires crypto, which may involve exchange fees.
- Withdrawal costs: Both are cheap. Kalshi ACH is free. Polymarket Polygon gas is negligible.
- Hidden costs: Polymarket has crypto conversion costs. Kalshi has none—it's pure USD.
Hidden costs most traders miss
The posted fee schedule doesn't tell the whole story:
Polymarket hidden costs:
- Crypto on-ramp fees: Buying USDC via MoonPay, credit card, or exchange costs 1-3%.
- Off-ramp fees: Selling USDC back to USD on an exchange costs another 0.5-1%.
- Slippage: On low-liquidity markets, your fill price can be worse than displayed.
- Bridge fees: If your USDC is on Ethereum mainnet, bridging to Polygon has a cost.
Kalshi hidden costs:
- Spread costs: Some markets have wide bid-ask spreads. You pay the spread implicitly.
- Opportunity cost: ACH deposits take 1-3 business days. You might miss a trade while waiting.
- Settlement delays: Payouts after market resolution aren't always instant.
Which platform is cheaper?
The answer depends on your trading style:
Polymarket is cheaper if:
- You already hold USDC and don't need to convert from/to USD.
- You use limit orders (0% maker fee).
- You trade frequently on high-liquidity markets.
- You don't mind managing a crypto wallet.
Kalshi is cheaper if:
- You're trading with US dollars (no crypto conversion).
- You value simple deposit/withdrawal via bank transfer.
- You prefer regulatory protection (FDIC-insured custodians).
- The all-in cost of crypto on/off-ramps would exceed Kalshi's trading fees.
Strategies to minimize fees on both platforms
- Use limit orders: On both platforms, maker fees are lower than taker fees. Place limit orders whenever possible.
- Trade liquid markets: Tight spreads mean less implicit cost. Stick to popular markets.
- Batch deposits: On Polymarket, deposit larger amounts less frequently to reduce per-trade on-ramp costs.
- Track your costs: Use a spreadsheet to record all fees paid (including conversion costs). Many traders underestimate their true cost.
- Compare before trading: Check both platforms' prices. Even with fees, the cheaper price might be on the other platform.
Compare prices with Alphascope
Alphascope shows you prices across both platforms so you can factor in fees and find the best deal:
- Predictions → See Kalshi and Polymarket prices side by side for the same markets.
- Arbitrage → Spot price gaps that might offset fee differences.
- News → Catch market-moving news to trade before spreads widen.
FAQ
Which platform has lower fees overall?
Polymarket has lower explicit trading fees (especially for makers), but Kalshi has lower all-in costs for traders who don't already hold crypto.
Does Kalshi charge withdrawal fees?
Standard ACH withdrawals on Kalshi are free. Wire transfers may have a fee depending on your bank.
Are Polymarket gas fees expensive?
No. Polymarket runs on Polygon, where gas fees are typically under 1 cent per transaction.
Do fees affect my arbitrage profits?
Absolutely. When calculating arbitrage between Kalshi and Polymarket, always subtract fees from both platforms. A 5% price gap might only be 2% after all costs.