Prediction Market Fees in 2026: Kalshi vs Polymarket

The fee difference between Kalshi and Polymarket looks small on paper until you run the numbers on an active trading month. A trader placing 50 contracts per week pays meaningfully different amounts on each platform depending on position size, market type, and whether they are making or taking liquidity. This guide breaks down the real cost structure of both platforms with actual trade examples, and shows where the fee differential creates exploitable arbitrage between them.

How Each Platform's Fee Structure Actually Works

Polymarket Fee Structure: The CLOB Model Explained

Polymarket operates a Central Limit Order Book (CLOB), a matching engine where orders trade directly against other users' orders, similar to how NASDAQ operates for equities. Unlike automated market makers that set prices algorithmically, the CLOB model lets supply and demand determine exact pricing in real time.

On most markets including politics, economics, entertainment, and the majority of sports, Polymarket charges zero trading fees and zero deposit or withdrawal fees for USDC. Polygon gas fees of roughly $0.01 to $0.05 apply for on-chain transactions, but these are negligible for the majority of traders.

Fees only apply to a subset of markets: 15-minute and 5-minute crypto direction markets, NCAAB college basketball markets created after February 18, 2026, and Serie A soccer markets created after the same date.

Key distinction: Makers place limit orders that rest on the order book and pay 0% in fees. They are also eligible for daily USDC rebates distributed from collected taker fees. Takers execute market orders that fill immediately and pay a variable fee based on contract price.

Polymarket taker fee formula: Taker Fee = 0.0625 x Price x (1 - Price)

This creates a parabolic curve that peaks at 50-cent contracts, because that is where uncertainty and fee revenue need to be highest to fund liquidity incentives.

For traders using the CFTC-regulated Polymarket US venue, the structure is simpler: a flat 0.10% taker fee on total contract premium, 0% maker fee, and a $0.001 minimum fee per trade. For a broader overview of what Polymarket offers beyond fee structure, see the Polymarket prediction markets guide.

Kalshi Fee Structure: The Exchange Model

Kalshi operates as a CFTC-designated contract market and uses a similar price-dependent formula, but with a higher coefficient. Kalshi taker fees are consistently higher than Polymarket taker fees across every price point as a result.

Kalshi taker fee formula: Taker Fee = 0.07 x Price x (1 - Price)

Maker fees on Kalshi vary by market. Most standard markets carry a 0% maker fee, but during major events such as NFL championships, NBA Finals, or presidential elections, Kalshi charges a flat 0.25% maker fee per contract. This removes the guaranteed rebate opportunity that Polymarket offers makers and increases the cost of holding positions through high-profile events.

Watch out: On contracts priced below 5 cents, Kalshi's 0.25% special event maker fee can represent 12 to 50% of the contract price. This makes longshot strategies prohibitively expensive on Kalshi during major events.

Kalshi also charges a 2% processing fee on debit card deposits and withdrawals, though ACH and wire transfers are free. For a full platform breakdown see the Kalshi trading strategies guide.

Real Cost Calculator: What You Actually Pay Per Trade

Percentage fees are abstract. Dollar costs are not. The table below shows the actual fee you pay for identical trades on each platform at the position sizes most active prediction market traders use.

Fee Comparison at Different Trade Sizes

Takeaway: On fee-enabled markets, Polymarket taker fees are consistently 30 to 40% cheaper than Kalshi across all price points and position sizes. On Polymarket fee-free markets, the saving is 100% because no fee applies at all.

How Fees Compound Over a Month of Active Trading

The dollar-per-trade difference compounds fast. The table below models three trader profiles across a full month.

For professional traders moving $100,000 or more in monthly volume, the annual fee gap runs to $12,000 to $15,000. The Polymarket trading strategies guide covers how to structure activity to minimise fee drag across both platforms.

Hidden Costs That Don't Show Up in the Fee Schedule

The official fee table is only part of the picture. Every platform carries costs that never appear in the documentation but hit your P&L all the same.

Bid-Ask Spread Width

Polymarket spreads on high-volume markets typically run 2 to 5 cents. Kalshi spreads on comparable markets are typically 3 to 8 cents wider, because Polymarket's zero maker fee policy attracts more passive liquidity providers. On a $1,000 position, a 3-cent wider spread costs $30 more to enter and exit regardless of the official fee rate.

Slippage on Large Orders

On orders of 5,000 contracts or more, Polymarket has deeper order book depth on major political and crypto markets with slippage running 1 to 2% on $5,000-plus fills. Kalshi's book is deeper on US sports markets where slippage on the same order size runs 2 to 4%. Maker rebates on Polymarket partially offset slippage costs on large fills. Kalshi has no equivalent mechanism.

Withdrawal Speed and Opportunity Cost

Polymarket USDC withdrawals are essentially instant, with Polygon gas fees of around $0.02. Kalshi ACH withdrawals take 1 to 3 business days. At a 2% monthly return, $10,000 locked in Kalshi for three extra days represents $20 in opportunity cost per withdrawal cycle. For traders who rotate capital quickly between opportunities, that friction adds up. The top Polymarket alternatives guide compares withdrawal terms across all major platforms.

Margin Requirements

Neither platform requires traditional margin. Both use binary contracts priced between $0.01 and $0.99, settled in USDC on Polymarket and USD on Kalshi, which eliminates margin call risk and interest charges from the cost comparison.

Where the Fee Difference Creates Arbitrage Opportunities

Fee differentials between platforms do more than affect individual trade costs. When the same event trades at different prices on Kalshi and Polymarket, the fee gap determines whether a spread is large enough to produce profit after costs on both sides. For a full execution guide see the Polymarket vs Kalshi arbitrage guide.

How Cross-Platform Arbitrage Works in Prediction Markets

If the same event with identical resolution criteria trades at different odds on each platform, you can take opposite positions simultaneously and lock in a guaranteed return regardless of outcome. One side pays out $1.00 per contract; the other loses its cost. The spread between the combined prices, minus fees, is your locked-in profit.

Example: 'Will Bitcoin close above $75K on Friday?' trades at YES 58c / NO 42c on Kalshi and YES 54c / NO 46c on Polymarket. Buying NO on Kalshi at 42c and YES on Polymarket at 54c costs a combined 96c per contract. One side pays out $1.00. That is a 4-cent gross profit per contract before fees.

The Fee Threshold for Profitable Arbitrage

At 50-cent contracts, where fees peak on both platforms, Kalshi taker fees run 1.75 cents per contract and Polymarket taker fees run 1.56 cents per contract. Combined fee cost is 3.31 cents. For 100 contracts you need a gross spread of at least $3.31 just to break even.

Worked example with a wider spread: Kalshi shows YES at 62c and Polymarket shows NO at 40c on the same market. Gross spread: 62 + 40 = 102c, giving 2c of profit per contract. For 100 contracts, gross profit is $2.00. Kalshi taker fees: 0.07 x 0.62 x 0.38 x 100 = $1.65. Polymarket taker fees (fee-enabled market): 0.0625 x 0.40 x 0.60 x 100 = $1.50. Total fees: $3.15. At 100 contracts this specific spread is not yet profitable. Scale to 1,000 contracts and the gross profit of $20 easily clears the $3.15 fee load, producing approximately $16.85 net profit.

General rule: Kalshi's higher fees raise the minimum viable spread for every arbitrage trade. Lower Polymarket fees mean you keep a larger share of each arb. This is why Polymarket is the better-structured platform specifically for arbitrage traders.

This relationship is explored in depth in the Kalshi vs Polymarket main comparison.

Current Arbitrage Monitoring: How to Find Live Opportunities

Manual monitoring involves identifying events listed on both platforms with identical resolution criteria, then comparing YES and NO prices to check whether the combined price exceeds 100 cents by more than the fee threshold. Elections, major sports finals, and Federal Reserve rate decisions produce the most overlap. Execute the Kalshi leg first because the platform is slightly slower to update, then immediately take the offsetting position on Polymarket.

Algorithmic traders and market makers close most arbitrage windows within 2 to 15 minutes. To catch opportunities before they close you need capital pre-loaded on both platforms, orders staged in separate tabs, and the discipline to execute within seconds.

Laika Labs' prediction market dashboard tracks live odds discrepancies between Kalshi and Polymarket in real time and sends alerts when spreads exceed your fee-adjusted profit threshold. Before deploying capital on Polymarket, check which jurisdictions have access using the Polymarket supported and restricted countries guide.

Which Platform Has Lower Fees for Your Trading Style

Best for High-Frequency Small Trades: Polymarket

Zero fees on 95% of markets mean hundreds of small trades per month cost nothing in platform fees. Even on fee-enabled markets, a $100 to $500 position pays $1 to $3 in fees versus Kalshi's $5 to $10. Over a month of high-frequency activity the saving compounds to hundreds of dollars.

Best for Large Position Sizing: Split Decision

Polymarket wins for politics and crypto markets, where deeper order books and tighter spreads reduce slippage on $10,000-plus positions. Kalshi wins for US sports markets including NFL, NBA, and MLB, where it holds significantly better liquidity depth. Route large political and crypto positions through Polymarket; route large sports positions through Kalshi.

Best for Arbitrage Trading: Polymarket

Lower taker fees mean arbitrage spreads need to be smaller to be profitable, which opens up more viable opportunities. Polymarket's instant USDC withdrawals also enable faster capital rotation between trades compared to Kalshi's 1 to 3 day ACH cycle. The full arbitrage playbook is in the Polymarket vs Kalshi arbitrage guide.

Best for Occasional Trading: Polymarket

A trader making 5 to 10 trades per month on standard markets pays zero in platform fees on Polymarket. Kalshi charges on every trade regardless of frequency, meaning even occasional users pay $20 to $40 per month. Unless your trades are concentrated in US sports markets where Kalshi's liquidity justifies the cost, there is no fee-based reason to use Kalshi for low-volume trading.

Fee Changes to Watch in 2026

Prediction market fees have shifted quickly as both platforms compete for volume and navigate regulatory oversight, and 2026 brings several developments worth tracking.

Polymarket

The POLY token launch expected in Q2 2026 is the most significant pending change. If Polymarket follows the Binance BNB model, token holders could receive 25% fee discounts at 500 POLY and 50% discounts at 5,000 POLY, with additional maker rebate bonuses for stakers. That would push the cost advantage further toward Polymarket for committed traders. Separately, expect more markets to transition from fee-free to fee-enabled as Polymarket expands its liquidity incentive program. The CFTC-regulated Polymarket US venue may also see fee increases to cover compliance overhead.

Kalshi

The most likely development is volume-based fee tiers as competition intensifies. Kalshi currently pays 3.75 to 4% APY on idle balances, which for a trader holding $10,000 generates roughly $400 per year and partially offsets the fee disadvantage for lower-volume traders. Fee credits for high-volume traders and maker fee reductions on standard markets are also possible as Kalshi works to close the cost gap.

Frequently Asked Questions

Are Kalshi fees higher than Polymarket fees?

Yes. Kalshi taker fees use a coefficient of 0.07 versus Polymarket's 0.0625. At 50-cent contracts, the most common price point for contested markets, Kalshi charges $1.75 per 100 contracts and Polymarket charges $1.56 per 100 contracts on fee-enabled markets. On Polymarket's fee-free markets, the gap is even larger because Polymarket charges nothing at all.

Does Polymarket charge fees on all markets?

No. As of 2026, fees on Polymarket apply only to a subset of markets: 15-minute and 5-minute crypto direction markets, NCAAB college basketball markets created after February 18, 2026, and Serie A soccer markets created after the same date. Politics, economics, and most other sports markets on Polymarket carry zero trading fees.

What is the Polymarket CLOB fee structure?

CLOB stands for Central Limit Order Book. On Polymarket's fee-enabled markets, makers (limit orders resting on the book) pay 0% and receive daily USDC rebates from collected taker fees. Takers (market orders that fill immediately) pay a variable fee calculated as 0.0625 x Price x (1 - Price). This peaks at 1.5625 cents per contract at 50-cent prices and declines toward zero as contracts approach 0 or 100 cents.

How much does it cost to trade 100 contracts on Kalshi vs Polymarket?

At a 50-cent contract price, taker fees are $1.75 on Kalshi and $1.56 on Polymarket for 100 contracts on fee-enabled markets. At a 30-cent contract price, the cost is $1.47 on Kalshi and $1.31 on Polymarket. On Polymarket fee-free markets the cost is $0.00 regardless of position size.

Can you arbitrage between Kalshi and Polymarket?

Yes. When the same event trades at different prices on each platform, taking opposite positions simultaneously locks in a risk-free spread. The minimum viable spread depends on the combined taker fees from both platforms. At 50-cent contracts, combined fees of roughly 3.31 cents per contract mean you need a combined YES plus NO price above $1.0331 to break even. Spreads close quickly, typically within 2 to 15 minutes, so execution speed and pre-loaded capital are essential.

Does Kalshi charge maker fees?

Most standard Kalshi markets carry a 0% maker fee. However, during major events such as NFL championships, NBA Finals, and presidential elections, Kalshi charges a flat 0.25% maker fee per contract. On contracts priced below 5 cents, this 0.25% fee can represent 12 to 50% of the contract price, making it a significant cost for traders holding longshot positions through high-profile events.

Which is better for prediction market trading, Kalshi or Polymarket?

For most traders, Polymarket offers lower fees, better liquidity on political and crypto markets, and instant withdrawals. Kalshi offers a regulatory advantage for US institutional traders, better sports market liquidity, and a 4% APY on idle balances. The best approach for active traders is to use both platforms and route trades to the venue with the better spread and liquidity for each specific market. For a full comparison see the Kalshi vs Polymarket guide.

What is the fee formula for Kalshi?

Kalshi taker fees are calculated as: Taker Fee = 0.07 x Price x (1 - Price). This means the fee peaks at 50-cent contracts ($0.0175 per contract) and declines symmetrically toward 0 and 100 cents. Special event maker fees use a flat 0.25% of total contract premium rather than this formula.

The Verdict

For the vast majority of traders, Polymarket is the cheaper platform. Zero fees on most markets, lower taker fees on fee-enabled markets, maker rebates, and instant free withdrawals add up to a meaningful annual cost advantage that compounds with volume.

Kalshi's edge is specific: US sports liquidity, regulatory clarity for institutional capital, and that APY on idle balances which can offset fees for traders who are not rotating capital frequently.

Arbitrage traders need both platforms. The fee differential is not just a cost difference; it is the mechanism that generates arbitrage opportunities in the first place. Understanding the fee-adjusted spread threshold is what separates profitable arb trades from ones that look attractive on paper but fail after costs. See the Kalshi vs Polymarket main comparison and the Polymarket trading strategies guide for the full framework.