Buying 100 contracts at 50¢ costs between $0.00 and $2.75 in fees, depending on the platform.
We read the published fee schedule of all nine platforms we review and priced the same order on each. At 90¢ the gap is wider in relative terms: price-based fees shrink toward the extremes, flat per-contract fees don’t. On ADI Predictstreet, paying the asking price instead of the midpoint cost more than the fee itself in a typical busy market; on Kalshi and Polymarket US, less. The fee is only part of the cost.
Fee schedules checked Oct 2, 2026; live order books sampled Oct 11, 2026, 7:56 AM ET. Updated weekly.
By Arthur Angelo, PredictionScout Research · Updated Oct 11, 2026, 7:56 AM ET
Key findings
- Three fee designs, very different results. Formula fees (Kalshi, Polymarket US, OG for most US markets, ADI Predictstreet, Novig’s live markets) peak at 50¢ and fall toward 1¢ and 99¢. Flat fees (FanDuel Predicts at 2¢ per contract, Fanatics Markets at up to 2¢, Underdog’s 1¢ commission) do not. ProphetX charges only when you win.
- At 50¢, 100 contracts cost $1.75 on Kalshi, $1.74 on Polymarket US, $1.50 on ADI Predictstreet, $2.00 on Fanatics Markets and $2.00 on FanDuel Predicts. Novig charges nothing on pre-game trades; ProphetX charges $1.00 only if the trade wins.
- At 90¢, the formula platforms drop to $0.63 (Kalshi) and $0.63 (Polymarket US), while FanDuel Predicts still charges $2.00 and Fanatics Markets $1.60. On a $90 stake, that is 2.2% vs 0.7%.
- Spreads. Median bid-ask spread across each exchange’s busiest markets right now: Kalshi 1.0¢ (all-in $1.85); Polymarket US 1.0¢ (all-in $1.63); ADI Predictstreet 3.0¢ (all-in $4.81). “All-in” is the median cost of buying 100 contracts at the asking prices on the book, plus the fee, compared with paying the midpoint.
- Two schedules changed in the last month. Polymarket US raised its taker coefficient to 0.0695 on October 1, 2026, and Fanatics Markets’ new table (September 2, 2026) caps fees at 2¢ per contract. Always check the order ticket: every platform shows the fee before you confirm.
Fees for the same order on every platform
Want your own numbers? Use our prediction market fee calculator to enter a contract count and price.
Fee for 100 contracts, by price
Buying 100 contracts as a taker (an order that fills immediately) and holding to settlement. Selling early costs another fee on most platforms (see notes).
| Platform | 5¢ | 10¢ | 25¢ | 50¢ | 75¢ | 90¢ | 95¢ | Source |
|---|---|---|---|---|---|---|---|---|
| Kalshi | $0.34 | $0.63 | $1.32 | $1.75 | $1.32 | $0.63 | $0.34 | Kalshi fee schedule (July 7, 2026 update) |
| Polymarket US | $0.33 | $0.63 | $1.30 | $1.74 | $1.30 | $0.63 | $0.33 | Polymarket US fee schedule (effective Oct 1, 2026) |
| FanDuel Predicts | $2.00 | $2.00 | $2.00 | $2.00 | $2.00 | $2.00 | $2.00 | FanDuel Predicts: How payouts work |
| OG | $0.33–$2.00 | $0.63–$2.00 | $1.31–$2.00 | $1.75–$2.00 | $1.31–$2.00 | $0.63–$2.00 | $0.33–$2.00 | OG Help Center: Fees & Limits |
| ProphetX | $0.00–$1.90 | $0.00–$1.80 | $0.00–$1.50 | $0.00–$1.00 | $0.00–$0.50 | $0.00–$0.20 | $0.00–$0.10 | ProphetX Trading Fees (v1.2, Oct 1, 2026) |
| Underdog Predict | $1.00–$1.33 | $1.00–$1.63 | $1.00–$2.31 | $1.00–$2.75 | $1.00–$2.31 | $1.00–$1.63 | $1.00–$1.33 | UDM LLC fee schedule (Feb 12, 2026) |
| Fanatics Markets | $1.40 | $1.60 | $2.00 | $2.00 | $2.00 | $1.60 | $1.40 | Fanatics Markets fee disclosures (effective Sept 2, 2026) |
| Novig | $0.00–$0.29 | $0.00–$0.54 | $0.00–$1.12 | $0.00–$1.50 | $0.00–$1.12 | $0.00–$0.54 | $0.00–$0.29 | Novig Help Center: Fees on Novig |
| ADI Predictstreet | $0.29 | $0.54 | $1.12 | $1.50 | $1.12 | $0.54 | $0.29 | ADI Predictstreet API docs: Fees |
How each platform charges
- Kalshi. Taker: 0.07 × contracts × price × (1 − price), rounded up. Resting (maker) orders are free unless the series carries maker fees (0.0175 × C × P × (1−P)). Some series use a different multiplier. No settlement fee. Source.
- Polymarket US. Taker: 0.0695 × C × P × (1−P), rounded to the cent (banker’s rounding). Makers receive a rebate of 0.0125 × C × P × (1−P). Taker rebates of 10–50% for $250k+ monthly taker volume. Combos use a higher curve. Source.
- FanDuel Predicts. 2% of the potential payout (2¢ per $1 contract) at checkout, whatever the price. The 2% fee also applies if you cash out early. Source.
- OG. US customers, most markets: taker 0.07 × C × P × (1−P), maker 0.0175 × C × P × (1−P), charged to open and again to close early. Crypto, FX, commodities and index markets: $0.02 per contract. Settlement fee waived. Source.
- ProphetX. 2% of net winnings per market on straight trades, charged only on winning positions. Parlays follow a separate parlay fee schedule. Source.
- Underdog Predict. Broker commission $0.01 per contract per side (opening or closing). Exchange fees are passed through on top; the UDX exchange fee is reported as 0.07 × C × P × (1−P), but we could not open UDX’s own fee schedule, so the high end of the range is unverified. Source.
- Fanatics Markets. Per-contract table from $0.00034 to $0.02 (the $0.02 maximum applies from 20¢ to 80¢), charged on every buy and sell, order total rounded up to the next cent. Source.
- Novig. Makers pay nothing. Takers pay nothing on pre-game straight trades; 0.03 × P × (1−P) on most live trades; 0.06 × P × (1−P) on futures and live NCAAF spreads/totals; parlay quotes include 0.10 × P × (1−P). Source.
- ADI Predictstreet. k × P × (1−P) per outcome token on both legs of every fill (maker and taker alike). The platform rate is published by its public API (k = 0.06). Source.
Live spreads on the exchanges with public order books
The 100 busiest open markets on each exchange at Oct 11, 2026, 7:56 AM ET: Kalshi and ADI Predictstreet ranked by 24-hour volume (ADI Predictstreet had fewer than 100 with any volume), Polymarket US by total dollars traded (its public market list has no 24-hour volume). We bought 100 YES contracts on paper at the asking prices in the book. FanDuel Predicts, OG, Underdog Predict, Fanatics Markets and ProphetX publish no public order-book API, and Novig’s requires credentials, so we cannot measure their spreads.
| Exchange | Two-sided books | Median spread | Spread of 1¢ or less | Median fee | Median cost vs midpoint | Median all-in | All-in, % of stake |
|---|---|---|---|---|---|---|---|
| Kalshi | 93 of 100 | 1.0¢ | 88% | $1.20 | $0.50 | $1.85 | 6.1% |
| Polymarket US | 100 of 100 | 1.0¢ | 95% | $1.02 | $0.50 | $1.63 | 4.1% |
| ADI Predictstreet | 34 of 99 | 3.0¢ | 0% | $1.33 | $3.50 | $4.81 | 15.0% |
Download the data
Fee table and live spread sample (CSV)
The fee for 100 contracts at seven prices on all nine platforms, with source links, plus every order book we sampled (best bid, best ask, spread, cost to buy 100 contracts, fee). Free to reuse under CC BY 4.0.
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Methodology
- Fees come from each platform’s own published schedule, linked above, read on Oct 2, 2026. The benchmark is a taker order for 100 contracts, held to settlement, with the platform’s own rounding rule. Deposit and withdrawal fees are excluded.
- Polymarket here means Polymarket US, the CFTC-regulated exchange available to U.S. customers. The international polymarket.com site has its own schedule.
- Ranges. Where the fee depends on the market type (OG, Novig), on whether you win (ProphetX), or on a pass-through we could not verify (Underdog Predict’s exchange fee), we show the low and high ends.
- Spreads are a snapshot of public order books (Kalshi trade API, Polymarket US gateway API, ADI Predictstreet public API). “Cost vs midpoint” is what you pay above the midpoint of the best bid and best ask when you buy 100 contracts at the asking prices on the book. Books with no bid or no ask, or with a midpoint under 2¢ or over 98¢, are left out of the all-in figures.
- Kalshi series multipliers. Kalshi fees use each series’ published fee multiplier from its API (most are 1).
- Not compared like-for-like. Each exchange’s busiest markets are different (Kalshi’s are mostly sports and economics, ADI Predictstreet’s mostly soccer and esports), so spreads describe each venue’s own markets, not the same event.
Cite this research
Suggested citation: PredictionScout. (2026, October 11). The True Cost to Trade on Prediction Markets: Fees and Spreads Compared. https://predictionscout.com/research/prediction-market-trading-costs/
For a chart or news story: “Source: PredictionScout analysis of public exchange data (https://predictionscout.com/research/prediction-market-trading-costs/)”
The data and charts on this page are free to reuse under CC BY 4.0 with a link back to this page. Fee data: each platform’s published fee schedule. Order books: Kalshi, Polymarket US and ADI Predictstreet public APIs.
Data sources: prices and volumes come from the public APIs of Kalshi and Polymarket, Polymarket US and ADI Predictstreet. All trademarks belong to their owners. PredictionScout is independent and not affiliated with any exchange. Nothing here is investment, betting, or legal advice.
Related: Fee calculator · Price gap index · Accuracy scorecard · All research