With Predictions powered by Polymarket US now live in the Betr app, it's worth knowing exactly when and how a fee applies before you place a trade.
Polymarket US charges a taker fee when your order removes liquidity from the order book. The exchange calculates the fee automatically when your trade executes and deducts it from your balance.
Polymarket US does not charge a fee to deposit or withdraw.
How the fee is calculated
The formula behind the standard taker fee looks like this:
fee = Θ × C × p × (1 - p)
C is the number of contracts in the trade, p is the trade price, and Θ (theta) is the fee coefficient. Θ is currently 0.0695 for most markets. A few markets use a different coefficient, listed on the Polymarket US fee schedule. Combos use a separate fee curve, shown on the Polymarket US fee schedule (https://docs.polymarket.us/fees).
Only takers pay a trading fee. Makers, whose resting orders are filled by someone else, do not pay a trading fee. Under the Polymarket US fee schedule, some makers and high-volume takers may also be eligible for rebates. Fees are subject to change; see the current Polymarket US fee schedule (https://docs.polymarket.us/fees) for details.
For single-market trades, because the fee scales with p × (1 - p), it is the same at mirrored prices: a trade at 30¢ carries the same fee per contract as a trade at 70¢. The fee is highest at 50¢ and lowest near 1¢ and 99¢.
How small can a fee get?
Fees are rounded to the nearest cent using banker's rounding. On small trades, or at prices near 1¢ or 99¢, the fee can round down to $0.00.
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Predictions on Betr are event contracts listed on Polymarket US (QCX LLC), a CFTC-designated contract market, and cleared through Polymarket Clearing (QC Clearing LLC). Betr provides the app you use to access Polymarket US. Betr is not the exchange or a broker. Trading event contracts involves risk, and you can lose the full amount you pay for a contract, plus fees. Each contract is governed by its contract terms and the Polymarket US Rulebook (https://polymarketexchange.com/files/legal/latest/rulebook).