Prediction Market Trading Fees Explained: Trading Fees Guide

A trading fee is the cost that a platform charges you to open, close, or hold a position on an event contract. Prediction market apps sell contracts priced between $0.01 and $0.99 that settle at either $1.00 or $0.00 once the underlying event resolves. That price reflects the market's implied probability of the outcome happening while the trading fee is a separate charge layered on top of that price. Fees are how platforms generate revenue since they aren't setting odds against you the way a traditional sportsbook does.

Trading fees show up in a few different forms depending on the platform:

• A percentage of the contract price, often weighted so it costs more to trade near a coin flip (50 cents) than near a lock (5 cents or 95 cents)
• A flat fee per contract, charged the same amount no matter the price
• A commission on net winnings, only charged if your trade actually profits
• A cost baked into the spread, where you don't see a line-item fee but pay more to buy or less to sell than the "true" price

How Are Trading Fees Charged?

Most CFTC-regulated exchanges use a formula tied to the number of contracts and the contract's price. The most common version looks like Fee = a fee rate × number of contracts × price × (1 - price)

On top of the base formula, most exchanges also separate fees by order type:

• Taker fees apply when your order matches instantly against an existing order on the book. You're "taking" available liquidity, so you pay the full fee.
• Maker fees apply when you place a limit order that sits unfilled until someone else trades against it. Because you're adding liquidity rather than taking it, maker fees are often reduced, waived entirely, or even paid back to you as a rebate.

Sports-focused exchanges like Novig and ProphetX use a different model entirely. Instead of charging a fee on every trade, they charge a commission only on net winnings, meaning a losing position costs you nothing beyond the money you put at risk.

Why Do Prediction Markets Charge Fees?

Trading fees exist because prediction market operators need a way to make money that doesn't involve setting a line against their users. A traditional sportsbook builds its profit margin, the vig, directly into the odds on both sides of a bet whereas at prediction markets, prices are set by the traders themselves through buying and selling.

It's worth noting that platforms adjust fee rates by category over time, so you shouldn't expext to pay the same fees forever.

While you can't completely avoid trading fees on most platforms, there are real ways to cut down what you pay:

Use Limit Orders

Placing a limit order and waiting for it to fill (acting as the "maker") usually costs less than a market order, and on some platforms it's free or even earns you a rebate.

Trade Near the Extremes When You Can

Contracts priced near 5 cents or 95 cents cost far less in fees than contracts priced near 50 cents, since most fee formulas are weighted toward market uncertainty.

Know Which Categories are Cheapest

Some platforms make certain categories, like geopolitics, completely fee free to encourage volume, while others, like crypto or sports, carry the highest rates.

Trade Less Often

Fees add up per trade, so frequent in-and-out trading on the same market costs more than fewer, well-researched positions.

Compare Exchange Fees to Commission Models

If you tend to lose more trades than you win, a platform that only charges on net profit, like Novig or ProphetX, may end up cheaper than a per-trade fee model, even if the per-trade fee looks small.

Watch Payment Method Fees Separately

Trading fees are only part of the cost. Some platforms charge extra for debit card deposits, while ACH bank transfers are typically free.

Fee schedules change often, so treat the numbers below as a snapshot as of October 2026 and always confirm the current rate on the platform before you trade.

Kalshi

Kalshi calculates its standard taker fee with the formula fee = round up(0.07 × contracts × price × (1 - price)), rounded up to the next cent. In plain terms, a contract trading at 50 cents costs the most per contract, while one trading near 1 cent or 99 cents costs close to nothing. Some categories, like certain index markets, use a reduced multiplier, and some special-event markets carry their own custom schedule. Kalshi also applies maker fees on markets where limit orders rest unfilled on the book, though these are typically lower than taker fees and are only charged once the order actually executes. There's no settlement fee and no fee on ACH deposits, though debit card deposits carry a processing fee.

Sign up with Kalshi promo code ROTOWIRE to get $25 when you trade $25.

Polymarket

Polymarket uses a taker fee formula of fee = C × p × (1 - p) × fee rate, where C is the number of shares and p is the price. Fee rates differ by category. Currently, geopolitical and world event markets are completely fee free for both makers and takers, while categories like finance and tech carry lower rates than sports and crypto, which currently sit at the higher end of the schedule. Makers, meaning traders who place limit orders that add liquidity, are never charged a fee on Polymarket, and those fees fund a Maker Rebates Program that pays daily rebates back to the traders providing that liquidity. There are no deposit or withdrawal fees from Polymarket itself, though outside services used to fund a USDC wallet may charge their own fees.

Sign up with Polymarket promo code ROTOWIRE to get a $25 bonus when you deposit $10.

OG Markets (OG.com)

OG.com, the standalone prediction markets platform from Crypto.com, uses a simpler flat-fee structure rather than a price-based formula. Reporting on OG's fee schedule generally points to a flat charge per contract to open a position and a matching flat charge to close it early, with fees waived entirely if the contract settles as a winner. That makes OG's cost structure more predictable trade to trade than curve-based formulas, though it's worth checking the current fee breakdown in the app since some markets and account types may vary.

Sign up with the OG promo code to get a $10 bonus when you trade $10.

Novig

Novig markets itself around a "no-vig," peer-to-peer model, and it holds up in the sense that Novig does not build a margin into the price the way a traditional sportsbook does. Instead, Novig earns money through a commission charged only on net winnings, meaning a losing trade costs you nothing beyond your original stake. When liquidity is thin and Novig steps in as a market maker to fill an order, a small spread can apply, but there's no standing commission charged on every trade.

Sign up with Novig promo code ROTOWIRE to gets you $50 when you deposit $10.

ProphetX

ProphetX runs a peer-to-peer sports exchange using American odds instead of probability-based pricing. Its fee model charges a small commission on net winnings for straight trades, while parlay trades typically carry no trading fee at all. As with Novig, you only pay when a trade actually wins, and the fee applies to your profit rather than your total stake, so a losing position never costs you a separate fee on top of the loss itself.

Sign up with ProphetX promo code ROTOWIRE to get $75 after trading a cumulative $50.

Understanding how prediction market fees work can help you compare platforms and estimate your real cost of trading. On most exchange-style platforms, the fee is disclosed separately from the price, so you can see exactly what you're paying for each contract rather than having it baked into the number you're quoted.

On commission-based platforms like Novig and ProphetX, you don't pay anything at all on a losing trade, since the fee only applies to net winnings. That's a meaningful structural feature: you only pay a fee when you actually profit from a trade, and the amount is disclosed upfront rather than folded into the price you see on the market.

Fees look small in isolation, but they compound the more often you trade. Here's a simple way to think about it:

Say you buy 100 contracts at 50 cents on a platform using the standard price-weighted formula. At a 7% fee rate, that single trade costs a little under $2 in fees. That might not sound like much against a $50 position, but if you're actively trading in and out of the same market multiple times a day, those per-trade costs stack up fast and can erode an edge that looked solid on paper.

The same logic works in reverse for commission-based platforms. If you rarely win, paying a commission only on net profit can end up cheaper over time than paying a fee on every single trade you make, win or lose. If you're a frequent, active trader who wins often, the math can tilt the other way. The right platform often depends less on which one has the "lowest" headline fee and more on how often you trade and how those trades tend to resolve.

No prediction market is truly free to trade on, but the platforms are far more transparent about their costs than a traditional sportsbook has ever been about the vig. Kalshi and Polymarket use a price-weighted formula that costs the most on 50-50 contracts and the least near the extremes, with maker orders offering a meaningful discount over market orders. OG Markets keeps things simple with a flat per-contract charge. Novig and ProphetX flip the model entirely, charging only when you actually win. None of these is objectively "the cheapest" for every trader. 

The best move is to understand how each platform charges before you fund an account, then match your trading style, whether that's frequent in-and-out trading or a handful of high-conviction positions, to the fee structure that rewards it.