For Polymarket Combos
Polymarket parlay calculator
Polymarket calls its parlays Combos. ComboCheck is a free calculator for them: pick your legs, enter the price Polymarket quoted, and see the fair price, the fee, how much over fair you would pay, and how your price compares with real combo trades.
Check your own combo quoteFree, no sign-in.
How to use it
- On Polymarket, build your combo and request a quote. Note the price per share.
- On ComboCheck, pick the same legs (Yes or No on each market).
- Type the quoted price in cents. You get the fair price, the fee, the all-in price, your margin over fair and a 0 to 100 deal score.
How the fair price is worked out
Each leg's probability comes from the midpoint of its Polymarket order book. The fair price of the combo is those probabilities multiplied together, which assumes the legs are independent. For example:
| Leg 1 | 60% (60¢) |
|---|---|
| Leg 2 | 45% (45¢) |
| Fair price | 0.60 x 0.45 = 27.0¢ |
| Quote | 30.0¢ |
| Taker fee | 0.05 x 0.30 x 0.70 = 1.05¢ |
| All-in price | 31.05¢ |
| Margin over fair | 31.05 / 27.0 - 1 = +15% |
Whether +15% is a good price depends on what similar combos go for, which is what the deal score measures.
What buyers pay right now
As of Nov 4, 2026, 21:27 UTC, pre-game combo buyers paid a median 9% over fair today, and same-game combos 27% over fair. Over the last 7 days, by number of legs: 2 legs +5%. 3 legs +7%. 4 legs +8%. 5–6 legs +11%. 7+ legs +20%. All of today's numbers.
What ComboCheck does and does not do
- It checks prices for Polymarket's own Combos. It is not a separate parlay platform and has no contracts of its own.
- It never asks for a wallet, private keys, API keys or funds, and places no bets. It only reads public data: Polymarket's market listings and order books, and combo trades on the Polygon blockchain.
- It is free and independent, and not run by Polymarket. Links to Polymarket carry ComboCheck's referral code.
Other kinds of Polymarket parlay tools
Some tools build or place parlays for you through a bot or a browser extension, which usually means giving them permissions on your account. Others are separate on-chain parlay platforms with their own contracts and settlement. ComboCheck does neither: it tells you whether the price you were quoted on Polymarket is fair, before you accept it.
ComboCheck also prices the same bet elsewhere, so you can see whether Polymarket is the cheap side at all: nine US sportsbooks with their vig divided out, Kalshi leg by leg, and Limitless packs, their equivalent of a combo.