# ComboCheck

> A free, independent tool that checks whether a Polymarket combo (parlay) quote is a fair price, and prices the
> same bet on Kalshi, on Limitless (where parlays are called packs) and at nine US sportsbooks. It shows the legs'
> fair price, Polymarket's taker fee, the buyer's margin over fair and a 0-100 deal score against real combo trades
> rebuilt from the Polygon blockchain. Independent, not run by Polymarket. Not financial advice.

## Key figures (as of Nov 4, 2026, 21:27 UTC)

- Pre-game combos today: median 9% over fair (9,164 trades)
- Same-game combos today: median 27% over fair (1,302 trades)
- By number of legs, pre-game, legs from different games, last 7 days:
  - 2 legs: median +5% (15,133 trades)
  - 3 legs: median +7% (8,585 trades)
  - 4 legs: median +8% (6,069 trades)
  - 5-6 legs: median +11% (6,090 trades)
  - 7+ legs: median +20% (4,824 trades)

## Pages

- [Polymarket parlay calculator](https://www.combocheck.xyz/polymarket-parlay-calculator): what the calculator does, a worked example,
  and what it does not do (no wallet, no custody, no bets placed)
- [Today's numbers](https://www.combocheck.xyz/stats): live margins over fair by number of legs and sport
- [FAQ](https://www.combocheck.xyz/faq): are Polymarket combos a good deal, how they are priced, fees, same-game combos
- [Methodology](https://www.combocheck.xyz/methodology): data source, fair price, fee, margin and deal score definitions
- [Polymarket vs Kalshi vs Limitless vs sportsbooks](https://www.combocheck.xyz/polymarket-vs-sportsbook-parlays): what the same parlay
  costs on each, with every book's vig divided out, Limitless packs priced against their own legs, and Kalshi as a
  per-leg second opinion
- [API and MCP server](https://www.combocheck.xyz/developers): free read-only JSON API; MCP server at https://www.combocheck.xyz/mcp (Streamable HTTP, no key)
  with tools search_markets, check_combo_quote, get_market_stats and get_popular_combos
- [App](https://www.combocheck.xyz/): check a specific combo quote (needs JavaScript)
- [GitHub](https://github.com/CinqDollarBill/polymarket-parlay-calculator): what ComboCheck is and how its numbers are calculated
- [Limitless packs](https://www.combocheck.xyz/limitless-packs): every pack Limitless is selling, priced against its own legs
- [Contact](https://www.combocheck.xyz/contact): write to combocheckxyz@gmail.com about a mispriced combo, a missing market or the API