Kalshi vs Polymarket: Fees, Regulation, Markets, and Key Differences

Quick Comparison

How Kalshi and Polymarket Are Regulated

This is the clearest difference. Kalshi’s status is relatively straightforward. The CFTC designated KalshiEX LLC as a contract market in November 2020, and granted Kalshi Klear LLC registration as a derivatives clearing organization in August 2024. In plain English, Kalshi has both a regulated exchange layer and a regulated clearing layer inside the U.S. commodity-derivatives framework. For a deeper look at how that structure works, see What Is Kalshi?

Polymarket is more complicated. In January 2022, the CFTC settled with Blockratize, Inc. — the original Polymarket operator — over off-exchange event-based binary options offered without complying with the Commodity Exchange Act. That is settled history and still matters for context.

Since then, the picture has changed. QCX LLC d/b/a Polymarket US was designated as a CFTC contract market in July 2025, and Polymarket’s current U.S. page says Polymarket US is operated by QCX LLC, while the better-known international Polymarket platform is separate and “not regulated by the CFTC.” That is the precise point many older comparisons miss.

The safest summary: Kalshi’s U.S. regulatory structure is more settled and easier to describe. Polymarket’s brand now spans both a separate regulated U.S. exchange entity and a distinct international platform. That distinction affects U.S. access, market scope, and how confidently you can generalize from one Polymarket product to another.

How Fees Compare

Kalshi’s main retail fee schedule is unusually transparent because it is formula-based. The standard taker fee is 0.07 × C × P × (1 − P), where C is the number of contracts and P is the contract price. Fees peak around mid-probability contracts and fall toward the extremes — a 50¢ contract carries more fee friction than a 5¢ or 95¢ contract. To see exactly how that formula affects a specific trade, use the Vig Calculator.

Polymarket’s fee model is less uniform. Most markets are fee-free, but certain categories — including crypto and some sports markets — have taker fees enabled to fund maker rebates. The cost structure depends more on what type of market you are trading than on one platform-wide formula.

The practical comparison: Kalshi is easier to model because its fee logic is published and broadly consistent. Polymarket can be cheaper in fee-free markets, but not every Polymarket market is fee-free. For a full side-by-side across platforms including PredictIt, see Prediction Market Fees Compared.

Market Selection

Polymarket built its reputation on internet-native event markets — especially politics, elections, crypto, culture, geopolitics, and fast-moving headline markets. That is why many users first encountered the brand through election odds. If you are looking for a wide set of public-attention markets tied to major news cycles, Polymarket has historically been the brand most associated with that experience.

Kalshi’s catalog is also broad, but tends to feel more structured around regulated event contracts: economics, weather, politics, sports, companies, and financial benchmarks. That does not mean Kalshi lacks breadth — it means the product mix often looks more U.S.-regulatory-first than the broader “anything people want to forecast” flavor associated with Polymarket. To convert any contract price into implied probabilities or familiar odds formats, use the Prediction Market Odds Converter.

US Access

Kalshi is the simpler story for U.S. users. It operates inside an established CFTC-regulated framework with onboarding, payment rails, and disclosures built around U.S. retail participation. That does not eliminate state-level disputes or category-specific restrictions, but it makes Kalshi the more straightforward platform to describe as a currently established U.S. option.

Polymarket’s U.S. status is more precise than many old articles suggest, but still newer and less settled. The accurate statement is not “Polymarket is illegal in the U.S.” and not “all Polymarket activity is now fully available nationwide through one unified regulated app.” The reality sits between those two extremes: Polymarket US runs through a separate regulated entity, is being rolled out from a waitlist, and the international platform remains distinct.

Parlays and Combos

Kalshi has a clear product edge here. Its Combos feature lets you bundle multiple event legs into a single position — similar in spirit to a parlay. Kalshi publicly lists combo markets across NFL, NBA, and Mention categories. To understand how parlay math works and evaluate whether a combo price is fair, use the Parlay Calculator.

Polymarket does not appear to offer an equivalent first-party combo or parlay product. That does not mean Polymarket could never add one — only that Kalshi currently has the cleaner, documented combo offering.

Liquidity

For most retail-sized orders, the right answer is “it depends on the market.” Both platforms can have usable liquidity in headline contracts and much thinner books in long-tail markets. Depth is not a platform-wide constant — it is highly specific to category, event importance, and timing.

Kalshi emphasizes regulated exchange structure and institutional liquidity support. Polymarket documents maker rebates funded by taker fees in eligible markets, which can tighten books in its more active categories. Both can be workable for modest order sizes in flagship markets, and both can get thin in smaller or more niche contracts.

Tax Treatment

Kalshi’s tax posture is more conventional from a U.S. paperwork standpoint. Users who meet IRS thresholds may receive forms including 1099-INT, 1099-MISC, 1099-B, and 1099-DA, depending on activity.

Polymarket can involve more tax complexity because the broader ecosystem has historically involved crypto and tokenized settlement mechanics. Neither platform should be treated as a substitute for actual tax advice.

What About PredictIt and Robinhood?

PredictIt remains a known U.S. prediction-market brand, but on fees it is much less competitive. PredictIt charges a 10% fee on profits and a 5% withdrawal fee — a meaningfully heavier friction stack than either Kalshi or Polymarket.

Robinhood is worth mentioning as a newer distribution channel. Robinhood says its event contracts are offered through licensed exchange and clearing relationships, including KalshiEX LLC and ForecastEX, LLC. It is important as a retail channel that can bring prediction markets to a much larger audience, but it is not yet best understood as a direct third-platform alternative to Kalshi or Polymarket.

Which Platform Fits Your Needs?

Kalshi may suit you if you care most about a clearly defined U.S. regulatory structure, a published formula-based fee schedule, USD-native rails, and products like Combos inside a CFTC-supervised environment.

Polymarket may suit you if you are drawn to the broader prediction-market ecosystem associated with politics, crypto, and viral markets, while recognizing that its U.S. setup now runs through a separate regulated entity and remains more layered. That is not a recommendation to open an account on either platform — it is simply the clearest 2026 comparison.

Frequently Asked Questions

Common questions about how Kalshi and Polymarket compare.