Kalshi · Polymarket · Novig · ProphetX
How prediction markets price NFL, NBA and MLB player props against DraftKings and FanDuel — and where the better de-vigged number is right now.
Right now BeatVig prices 5,386 NFL, NBA and MLB player props at both. A prediction market is the better price 39% of the time (2,130 of 5,386). This is the board as it stands at 31 Oct 12:16 ET, not an average over any period — BeatVig measures live prices and keeps no price history.
Same outcome, two business models.
A sportsbook sets a price and builds its margin into both sides — that margin is the vig, and it is the reason a coin flip is priced at -110 instead of +100. A prediction market does something different: Kalshi, Polymarket, Novig and ProphetX match one trader against another and charge a fee on the trade, so the quote you see is closer to what the market actually believes.
That difference is worth money on the props you were already betting. BeatVig converts every quote — book and exchange — to implied probability, removes the vig from both, and flags the ones where the exchange is the cheaper side of the same outcome.
Straight off the board, no cherry-picking.
ProphetX
+26527.4%27¢
vs
Hard Rock Bet
+19533.9%34¢
· +6.5pp vs Hard Rock Bet
fair 33.5% · edge +5.66pp (worst case +3.93pp) — this edge is 5.66 percentage points under the de-vigging method BeatVig publishes and as little as 3.93 under the least flattering of the 4 methods that fit Bovada's own two-sided prices
ProphetX
+22031.3%31¢
vs
Bovada
+15040%40¢
· +8.75pp vs Bovada
fair 37.3% · edge +5.57pp (worst case +4.75pp) — this edge is 5.57 percentage points under the de-vigging method BeatVig publishes and as little as 4.75 under the least flattering of the 4 methods that fit Kalshi's own two-sided prices
ProphetX
+28026.3%26¢
vs
Hard Rock Bet
+17536.4%36¢
· +10.05pp vs Hard Rock Bet
fair 32.3% · Bovada, multiplicative devig
Free accounts see a 3-edge sample from below the top of the board. Premium unlocks the full board, every sport, every venue.
Go PremiumHow each one charges you, and where it prices which sport.
Which venue is currently the cheaper side.
Across the 5386 player props BeatVig prices at both a prediction market and a sportsbook right now, a prediction market is the better price 39% of the time (2130 of 5386). That is a live count of the current board rather than an average over time, and a sportsbook is still the better number on the rest.
Kalshi charges a per-contract trading fee rather than a flat cut of winnings, and the fee is a curve that peaks at roughly 1.75 cents on a contract priced near 50 cents and shrinks toward zero at both extremes. A sportsbook's margin is inside the price instead, so you pay it on every bet whether it wins or loses.
Kalshi lists player markets as "X or more" yes/no contracts rather than as over/under lines, and Polymarket's player-prop coverage is still filling in. BeatVig converts each contract to the equivalent over price so it can be compared to a sportsbook number directly.
Convert both to the implied probability of the same outcome, then remove the sportsbook's vig so the two numbers mean the same thing. The cheaper venue is the one implying the lower probability for the side you want.
Kalshi and Polymarket US both operate through CFTC-regulated exchanges rather than under state sports-betting licences, which is why their footprint differs from a sportsbook's. Availability still varies by venue and by state, so check the venue before assuming you can trade there.
The props people actually shop for.
