A price is a number. Behind it are three you can't see.
Every market quote looks simple. But the same bet can cost more here than there, carry a house edge baked into the spread, and settle on rules that don't mean what you think. PolyEdge surfaces all three — in plain English, in about two seconds.
You're overpaying the spread.
Between the buy and sell price sits a hidden cut. On a thin market it can quietly skim several percent the instant you click.
The same contract, cheaper.
Polymarket and Kalshi price the identical event at different numbers all day. We find the gap — and only call it an edge if the resolution rules truly match.
The rules that burn you.
"Wins the nomination" and "is the nominee on election day" are different bets. We read the settlement terms and flag the traps before you're in.
Many prices in. One honest number out.
Scroll and watch the venues collapse into a single fair value. That's the whole engine: strip each venue's vig, weigh them by how sharp they are, and blend them in log-odds space — anchored on the de-vigged sportsbook line, the deepest market on earth.
- 01
De-vig every venue
Remove the house edge so each price becomes an honest probability.
- 02
Blend, weighted by sharpness
A multi-book sportsbook consensus outweighs a thin prediction market — never a naive average.
- 03
Return a value and a band
One number, plus a confidence range set by how much the venues actually disagree.
One engine. Three ways in.
The same honest read, wherever you are — on our site, right on the market page, or wired straight into your own tools.
The checker
Paste any market link and get the full read — chances explained, real cost to enter, the fine print, and a sensible amount to put in.
Check a market → both venuesThe extension
Our read paints itself right on the Kalshi or Polymarket page you're already on — the grade, the cost, the cheaper-elsewhere check, at the moment you're about to bet.
Get the extension →The API
The de-vigged cross-venue fair value as a metered endpoint — for your bots, dashboards, and models. Neutral third parties only.
Read the API docs →We write our number down before the outcome.
Anyone can look sharp in hindsight. So we publish every fair value in advance, into an append-only ledger where each entry is hash-chained to the last — change a past number and the whole chain breaks. When a market settles, you'll see whether we beat the venue's closing price. Grade us on the record, not the pitch.
Paste a market. Get the truth.
Two seconds, no account, no picks. Just the real price of the bet in front of you.