A sportsbook builds its cut into the odds. A prediction market usually charges a separate trading fee instead, so the price on the screen isn't always the price you get. On a close game the fee is worth a point or two of odds, which can be the difference between a prediction market and a sportsbook being the better bet.
How the fee works
Kalshi, Polymarket, Polymarket US, OG and Novig all use the same shape of fee, charged when your order takes a price that is already on the book (a taker or market order):
fee per contract = rate × price × (1 − price)
The fee is largest at 50¢ and shrinks toward 1¢ and 99¢. An order that rests on the book and gets filled later (a maker or limit order) pays a smaller fee or none.
| Venue | Taker fee on sports | Maker (limit) orders |
|---|---|---|
| Kalshi | 0.07 × price × (1 − price) | 0.0175 × price × (1 − price) |
| Polymarket | 0.05 × price × (1 − price); NFL and college football games 0.03 | No fee |
| Polymarket US | 0.0695 × price × (1 − price) on every market since October 19 | No fee |
| OG | 0.07 × price × (1 − price), charged again if you close early | 0.0175 × price × (1 − price) |
| Novig | No fee on a pre-game straight bet; 0.06 × price × (1 − price) live and on futures | No fee, plus a credit on live and futures fills |
| ProphetX | 2% of a winning bet's profit | Same |
Rates as of November 1, 2026, from each venue's published schedule. Rates can differ by sport, and venues run promotions and change them. For each venue's current rate in every sport, the promotions running now and what the fee costs at each price, see Prediction market fees. Check the venue before a big order. When Show prices after fees is on, each price uses its own sport's rate.
What it does to the odds
| Price | Odds before fees | Kalshi after fees | Polymarket after fees |
|---|---|---|---|
| 30¢ | +233 | +218 | +222 |
| 50¢ | +100 | −107 | −105 |
| 70¢ | −233 | −250 | −245 |
Buying 100 contracts at 50¢ ($50) costs about $1.75 in fees on Kalshi and $1.25 on Polymarket.
How Unjuiced shows it
- Kalshi odds in our book comparisons already include the taker fee, so a 50¢ contract shows as −107. Hover the price and the bet slip shows the contract's own price and the fee: "Trades at 50¢ · Price includes the 1.7¢ taker fee".
- ProphetX prices already include its 2% commission.
- Polymarket, Polymarket US, OG and Novig prices are the venue's own price, the same number you'll see in their app. Hover the price and the bet slip shows the payout after the fee ("$100 wins $95.12 after fees") and the odds after it ("Plus 1.3¢ taker fee: −105 after fees").
- On the Odds Screen's live board, Novig's live taker fee is used. Pre-game, the slip says Novig charges nothing.
- On +EV, Soft Lines, Arbitrage and Middles, hover a prediction market's price or leg for the same fee line. With the setting below off, an arb, middle or +EV bet with a Polymarket, Polymarket US, OG or live Novig leg is priced before that leg's fee, so check the odds after fees before you bet it.
Show prices after fees
To see every prediction market priced the way you'd actually pay it, turn on Show prices after fees in Settings › Display or the Odds Screen's View menu. Accounts created from November 1, 2026 start with it on. Polymarket, Polymarket US, OG and live Novig prices then include the taker fee at that sport's rate, so Polymarket's 50¢ (+100) shows as −105 · 51¢ on an MLB game and as −103 · 51¢ on an NFL game, where Polymarket charges 0.03. Kalshi and ProphetX prices already include theirs, so they don't change.
With the setting on, every tool also works from those prices, so what's marked best and every number worked out from a price match what you'd actually pay:
- Best prices and sorts: the Odds Screen's Best column, best-price marks and price sorts, and the best price on Hit Rates, the cheat sheets, Games, Ladders, Sharp Intel, the bet slip and Today go to the book that pays most after fees. A Polymarket price can lose Best to a sportsbook once its fee is in.
- +EV: a Polymarket, Polymarket US or live Novig bet shows its EV after the fee, and the minimum EV filter, the sort, profit boosts and the Kelly stake use it. Bets that drop below your minimum leave the list.
- Soft Lines: a prediction market's edge, boosted edge and stake are worked out from its price after the fee.
- Arbitrage and Middles: the profit, worst case, middle return and stake split use what each leg pays after its fee, in the list and in the side panel's calculator. The calculator's odds fields still show the posted price, with the price after fees under it. An arb the fee turns into a loss drops out of the list.
- Implied odds and hit rates: the implied chance next to a price, and your hit rate against it, read the price after the fee.
Some things stay as posted: the price a link opens at the book, a bet you've tracked (it's recorded at the price the venue quoted), fair and no-vig prices, and Sharp Intel's entries, moves and CLV. On +EV and Soft Lines, the book a row leads with is still picked before fees, and the NHL research sheets pick their best book before fees too. Alerts use each venue's posted price.
Promos always count fees, whatever this setting says: a bonus bet conversion or a hedged boost stakes a Polymarket US or Polymarket hedge from its price after the fee. Only the prices Promos prints follow the setting.
The fee shown is a taker's. If you post limit orders and get filled as a maker, you'll pay less than the slip shows, or nothing.
New to prediction markets? Start with Prediction markets vs. sportsbooks.