The basics
Two kinds of prices for the same game
Sportsbooks like DraftKings and FanDuel set odds themselves and build in a margin so they profit no matter who wins.
Prediction markets like Kalshi and Polymarket work differently: people trade contracts against each other, and the price is whatever buyers and sellers agree on. A contract costs somewhere between 1¢ and 99¢ and pays $1 if it wins.
What Level looks for
Sometimes the two kinds of venues disagree about the same game. When they disagree enough, you can back one team on a prediction market and the other team at a sportsbook, splitting $100 between the two so that both outcomes pay back roughly the same amount — more than the $100 you put in.
Level checks every pairing using the latest prices available and only shows a card when the estimated result is still positive after the fees and price-movement costs described below.
Any two venues can pair up, not just a prediction market against a sportsbook. Kalshi and Polymarket often disagree with each other too, and those pairings work exactly the same way — one side on each. Esports run entirely this way, since no sportsbook prices them.
A worked example
Numbers exaggerated so the math is easy to follow — real gaps are usually much smaller.
Kalshi is selling “Chiefs win” contracts for 42¢ each. FanDuel is offering the Ravens at +140 (bet $100 to win $140).
Level splits $100 so both outcomes pay back the same:
You put in $100
$50 → 119 Chiefs contracts, Kalshi
$50 → Ravens at FanDuel
Either result pays back about $119
If the Chiefs win, the contracts pay about $119. If the Ravens win, the FanDuel bet returns about $119. Either way you get back roughly $119 on $100 — about $19 before costs.
Two things come off that. The 42¢ is only the price of the first few contracts, so Level walks Kalshi’s order book and prices all 119 at what they would really fill at — if the cheap ones run out, the payout it shows drops accordingly. Then it subtracts Kalshi’s trading fee, about $2 here. The number on the card is what’s left, never the $19.
What we subtract before showing you a number
- KalshiTheir published trading fee, which is largest on a coin-flip contract and shrinks towards either end of the market
- Polymarket2% of what you spend
- The bookPrices are taken from the real order book level by level, not from the headline quote, so a thin market shows the worse average price you would actually fill at
- RoundingContracts come in whole numbers, so we round in the direction that works against the estimate, not for it
The number on every card is what’s left after all of that. We never show the bigger before-costs number as the headline.
AI-assisted scouting
AI double-checks the match, not the math
Once a gap clears the cost bar above, AI reviews the pairing itself: does the other leg actually look like the same real-world matchup as the prediction-market contract, and does its price look current rather than stale? Cards get a quick badge — verified, or flagged for a second look before you stake.
The AI never touches prices, fees, or the profit number. That part stays plain arithmetic, the same math described above, every time.
Plans
Free vs. Pro
The board is free to watch. You get one live opportunity, the widest gap open at that moment whatever sport it is in, refreshed every fifteen minutes. Pro is $29 a month and shows you all of them, a minute fresher. See what each plan includes.
The catch
- Prices move fast. A gap can disappear before you finish placing both orders — sometimes in seconds.
- If one order fills and the other doesn’t, you’re holding a one-sided bet, not a hedge.
- Sportsbooks may limit accounts that consistently take these prices.
- Prediction-market eligibility varies by state and jurisdiction — verify yours before trading.
- Nothing here is guaranteed. These are estimates from public prices at a moment in time.