Prediction Market Math
FEE SCHEDULES CHECKED 22 OCT 2026

Prediction Market Fees in 2026: What a Trade Costs on Each Venue

Polymarket, Polymarket US, Kalshi, PredictIt, Betfair, Smarkets and 1win Markets compared from their official fee pages, with sources and dates. We found no published fee schedule for 1win Markets (its rules pages were geoblocked from our location), so we measured the margin in its odds.

Topic illustration: Prediction Market Fees in 2026: What a Trade Costs on Each Venue
Conceptual illustration. Assumptions and numerical examples are explained in the text.
Illustrative fee per 100 contracts
F = N × r × p × (1 − p), N = 100, r = 0.07. Hypothetical rate, not a current tariff.

Fee Schedules by Venue

Every row comes from the venue’s own fee page, checked on 22 October 2026. The 1win row is our own measurement: we found no published 1win fee schedule.

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Venue Type Fee on the trade Fee on winnings or redemption Deposits and withdrawals Source and date
Polymarket (international) Exchange with an order book Taker: contracts × rate × p × (1 − p). Rate 0.07 crypto; 0.05 sports, economics, culture, weather and other; 0.04 politics, finance and tech; 0 geopolitics. At 50¢ that is 0–3.5% of the amount. Maker: 0% plus a rebate. None. A winning share redeems for 1 pUSD. No Polymarket fee on USDC deposits and withdrawals; gas for default wallets is paid by Polymarket’s relayer. docs.polymarket.com/trading/feesdocs.polymarket.com/changelog 22 Oct 2026
Polymarket US CFTC-regulated exchange, US residents only Taker: 0.0695 × contracts × p × (1 − p) since 17 September 2026 (0.06 before). Makers receive a rebate. None listed. Not checked. cftc.gov (QCX rule filing) 22 Oct 2026
Kalshi CFTC-regulated exchange Taker: 0.07 × contracts × P × (1 − P), rounded up to the cent: 3.5% of the amount at 50¢, 6.3% at 10¢, 0.7% at 90¢. Maker: free by default. None: Kalshi has no settlement fee. ACH free; debit card deposits up to 2%. International accounts deposit by card, crypto or wire and withdraw by card or crypto. kalshi-fee-schedule.pdfhelp.kalshi.com (transfers) 22 Oct 2026
PredictIt US exchange None. 10% of profit when you sell above cost or a share pays $1. Nothing on losing or break-even trades. Withdrawals from active accounts free; card deposits 3%. The 5% withdrawal fee applies only to accounts inactive for 12 months or more. predictit.org/supportpredictit.org/terms 22 Oct 2026
Smarkets Betting exchange None. 2% of net profit on a market (Standard). 1% on the Pro Tier for very active accounts; 3% above £25,000 profit in 12 months. Not checked. help.smarkets.com 22 Oct 2026
Betfair Exchange Betting exchange None. Commission on net market winnings. The rate depends on region and loyalty package (2% in Betfair’s European example; 6–10% in Australia). Expert Fee of 20–40% for fewer than 0.5% of customers. Not checked. betfair.com (charges)betfair.com.au (commission) 22 Oct 2026
1win Markets Fixed-odds bookmaker line, no order book No separate fee. The margin is in the odds: median 7.5%, expected loss about 7% of the stake (our snapshot of 76 questions, 21 October 2026, one location). None separate; you are paid at the fixed odds. Not verified: 1win’s rules were not reachable from our location. cross_venue_fee_and_spread_matrix.csv 21 Oct 2026
COST OF ONE TRADE // INTERACTIVE

What One Trade Costs on Each Venue

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Enter your stake and the price of the side you buy. The calculator applies each venue’s published formula and our 1win snapshot. It assumes the price equals the true probability and that you hold the position to resolution.

50¢
Venue and order type Expected cost % of stake Break-even probability
Polymarket, taker - - -
Polymarket, maker (limit order) - - -
Polymarket US, taker - - -
Kalshi, taker - - -
PredictIt (10% of profit) - - -
Smarkets Standard (2% of profit) - - -
1win Markets (median margin 7.5%) - - -

Not included: the bid-ask spread on exchanges, deposit and withdrawal costs, and Kalshi’s maker fee on the few series that have one. The 1win cost uses the median of our 21 October 2026 snapshot; the odds on a given question can be better or worse. Above 92¢ and at 1¢ the 1win odds hit their limits (1.01 and 91), so the calculator shows n/a there.

How We Compare Costs

Polymarket, Polymarket US and Kalshi charge the taker a fee on each trade. It depends on the price p of the contract:

fee = contracts × rate × p × (1 − p) → share of the amount paid = rate × (1 − p)

That is why the same rate costs more on cheap contracts: at the 0.07 crypto rate, a trade at 50¢ costs 3.5% of the amount, at 10¢ 6.3% and at 90¢ 0.7%. PredictIt, Betfair and Smarkets take a commission c only from profit, so you pay nothing on a loss. If the price equals the true probability and you hold to resolution, the expected commission is c × (1 − p) of the stake, the same shape as the trade fee.

break-even probability: fee on the trade p × [1 + rate × (1 − p)]; fee on profit p / [p + (1 − p)(1 − c)]

1win Markets charges no fee but pays at fixed odds. The margin is how far the implied probabilities of Yes and No together exceed 100%:

margin m = 1/odds_yes + 1/odds_no − 1 → expected loss at fair odds = m / (1 + m)

In our snapshot the median margin was 7.48%, so the median expected loss was 6.96% of the stake on either side. The exchange numbers leave out the bid-ask spread, which adds to the cost of every taker trade; at 1win the margin plays that role.

Three Ways Venues Get Paid

1. Fee on the trade (Polymarket, Polymarket US, Kalshi)

The taker pays when the order fills, win or lose. Makers who post limit orders pay nothing on Polymarket and, by default, on Kalshi. Redemption and settlement are free on Polymarket and Kalshi; Polymarket US lists no such fee.

2. Commission on winnings (PredictIt, Betfair, Smarkets)

Trading is free; the venue keeps part of the net profit on a market. PredictIt takes 10%, Smarkets 2% on a standard account, Betfair a rate set by region and loyalty package.

3. Margin in the odds (1win Markets)

A bookmaker line with fixed odds. There is no separate fee, but the odds pay less than the probability implies. The “chance” 1win displays is not the price: in our snapshot a question shown as 15% / 85% had odds of 6.1 / 1.07, which work out to 16.4% / 93.5%.

Where Polymarket and Kalshi Are Closed

Polymarket blocks trading entirely in Iran, Syria, Cuba, North Korea, Crimea and the Donetsk and Luhansk regions. In Australia, Belarus, Belgium, Brazil, France, Germany, Italy, Poland, Russia, Singapore, Slovakia, Taiwan, Thailand, the UK, the US (where Polymarket US is a separate exchange), four Canadian provinces and several other countries it only lets users close existing positions.

Kalshi does not accept trading from around 45 countries and territories, including Australia, Belarus, Canada, France, Poland, Russia, Singapore, Taiwan, Thailand, the UK and Venezuela.

Both lists change, so check the official pages before you sign up (checked 22 October 2026):

If Neither Is Open Where You Live

1win Markets lists Yes/No questions on many of the same topics: elections, crypto prices, sports, geopolitics. Before you use it, know what it is: a fixed-odds bookmaker line, not an exchange. There is no order book and no limit order, and in most of our comparisons it costs more than a taker trade on Polymarket or Kalshi.

We could not confirm in which countries 1win Markets is open: its rules were closed to us by geoblock. Check that 1win is licensed and legal where you live. Do not get around a block with a VPN: it breaks the venues’ terms.

See whether 1win Markets is open in your country →

Frequently Asked Questions (FAQ)

Does Polymarket take 2% of winnings?

No. Polymarket charges nothing on redemption: a winning share pays exactly 1 pUSD. Between January and March 2026 it introduced a taker fee on trades: contracts × rate × p × (1 − p), with rates from 0 (geopolitics) to 0.07 (crypto). Makers pay nothing and receive rebates. The “2% of winnings” figure that circulated earlier, including on this site until October 2026, is wrong.

How much does Kalshi charge per contract?

Takers pay 0.07 × contracts × P × (1 − P), rounded up to the next cent: $1.75 on 100 contracts at 50¢ and $0.63 at 10¢ or 90¢. Makers trade free unless Kalshi gives a series a maker fee. There is no settlement fee, and ACH transfers are free (Kalshi fee schedule effective 7 July 2026).

Is 1win Markets free of fees?

It has no separate fee, but the price is built into the odds. In our snapshot of 76 two-sided questions on 21 October 2026, the median margin was 7.5%, an expected loss of about 7% of the stake at fair odds. A Polymarket taker would have paid about 2–3.5% at the same prices. The snapshot comes from one location and one moment, so odds elsewhere may differ.

Why does the fee percentage change with the price?

Because the fee per contract is proportional to p × (1 − p), while you pay p per contract. As a share of what you spend, the fee is rate × (1 − p): small on favourites, large on longshots. At Polymarket’s crypto rate of 0.07, buying at 90¢ costs 0.7% of the amount and buying at 10¢ costs 6.3%.

Can I use 1win Markets if Polymarket and Kalshi are blocked in my country?

Possibly. The official Polymarket and Kalshi country lists are linked in the section above. 1win Markets offers similar Yes/No questions, but we could not confirm its country list, and 1win itself is closed in some countries under its gambling licence. Check that it is legal where you live, and remember that you pay the margin in the odds.