Polymarket tennis fees explained

On Polymarket's tennis markets you pay a fee only when your order fills straight away against the order book. The fee is 5% of your shares, scaled by the price: shares × 0.05 × price × (1 minus price). Orders that wait on the book and get filled later pay nothing. That's the whole rule. The rest of this guide shows what it costs in dollars and how it changes the price you need to break even.

I checked these figures on live ATP, WTA and ITF match markets through Polymarket's public API, and on Polymarket's own fee page, on 22 October 2026. Fees change. Before you trade real money, look at the fee page yourself.

Who pays: takers, not makers

Every trade has two sides. The maker places an order at a price and waits. The taker comes along and accepts it. On Polymarket, makers pay no fee at all. Only takers pay. So if you place a limit order at 60¢ and the market comes to you, you pay nothing. If you place a market order and take the 60¢ on offer right now, you pay the fee.

Polymarket also runs a maker rebate, which hands a share of the fees back to people who provide liquidity. For tennis the published rebate rate was 15% when I checked. That's for active market makers, not something a casual trader needs to plan around.

The formula, in plain words

The fee is worked out per trade:

fee = shares × 0.05 × price × (1 minus price)

The price × (1 minus price) part is what makes it interesting. It's largest at 50¢ and shrinks as the price moves toward 1¢ or 99¢. So the fee is highest on close matches and lowest on heavy favourites and long shots. It's symmetric: a trade at 30¢ costs the same fee as a trade at 70¢.

Notice the last column. In dollars the fee is biggest at 50¢, but as a share of what you spend it's biggest on cheap shares. Buying an underdog at 10¢ costs you 4.5% in fees. Buying a favourite at 90¢ costs 0.5%. Fees are charged in dollars (USDC) and rounded to five decimal places, so tiny trades at the extremes can round to nothing.

When you pay it

You pay on the way in and on the way out, if both orders are taker orders. Buy with a market order: fee. Sell with a market order: fee again. Hold to the end instead: no second fee, because a payout at settlement isn't a trade. Polymarket's fee page only describes fees on orders that take liquidity, so I treat the settlement payout as fee-free. Check that for yourself before you count on it.

That gives you two easy ways to pay less. Use limit orders when you're not in a hurry, and hold winners to the end when you're happy to.

How fees move your break-even price

Your break-even is the sell price at which you get back exactly what you paid. Without fees, it's the price you bought at. With fees on both sides, it's a little higher. The gap depends on where you bought:

So on a close match, the price has to move about 2.5¢ in your favour before you've made anything. That's roughly one good service game. It also means that if you buy and sell inside the same game, you'll usually lose a little even when your read was right. Add the spread, the gap between buy and sell prices, and the bar is a bit higher again. The profit calculator lets you put in a fee and see your break-even for any trade.

Why small trades suffer most

The fee itself scales with your trade, so a $5 trade pays a tenth of what a $50 trade pays. The spread scales too. What doesn't scale is the 5-share minimum. If you want to sell 3 shares to trim a position, you can't. And on thin markets, the fee is the least of your worries: a wide spread on a small ITF match can cost you 5¢ a share before any fee is counted.

Fees compared with a bookmaker's margin

A bookmaker doesn't charge a fee. It builds its profit into the odds, so the implied chances of both players add up to more than 100%, often 105% or more. That's a cost of 5% or so on every bet, win or lose. On Polymarket the two prices add up close to 100% on busy matches, and you pay the fee on top. For a close match that's about 2.5% each way with market orders, and nothing with limit orders. For details, see tennis trading vs tennis betting.

How the demo differs

The 77 Tennis demo charges no fee and has no spread. It fills you at the displayed price, both ways. I did that to keep practice simple, but it means demo results flatter you a little. A strategy that makes 2¢ a trade on the demo would lose money on the real market. When you test an idea on the demo, ask whether it still works after 2 to 3¢ of costs on each round trip. If it only just works on the demo, it won't work for real.

If you're planning your first real trade, the step-by-step guide walks through the whole process, fees included.

FAQ

How much is the Polymarket fee on a tennis trade?

Shares × 5% × price × (1 minus price), on orders that fill straight away. At 50¢ that's $1.25 on 100 shares. At 90¢ it's 45¢. Makers pay nothing.

Do I pay a fee when the match settles?

Polymarket's fee page only describes fees on trades that take liquidity. A settlement payout isn't a trade, so I treat it as fee-free. Check the fee page yourself before you rely on that.

How do I avoid the fee?

Place limit orders and let the market come to you. Orders that wait on the book pay no fee. You might not get filled, though, and in a fast match the price can run away from you.

Does the demo charge fees?

No. The 77 Tennis demo fills you at the displayed price with no fee and no spread. Real results would be a little worse, so allow 2 to 3¢ per round trip when you judge a demo strategy.