Polymarket vs Kalshi: fees, access and settlement
Overview
Polymarket and Kalshi both let people trade contracts on future outcomes, but the same headline does not mean the same contract. Choose by your eligibility, funding needs, total costs and the rules of the specific market—not by a platform-wide claim that one is always cheaper or better.
The short answer: which platform should you consider?
Start with access. Kalshi operates as a US-regulated exchange and has country-specific account requirements. Polymarket.com has its own geographic restrictions; Polymarket's separate US product is not interchangeable with the international platform. This comparison concerns Polymarket.com and Kalshi, not a review of Polymarket US.
If both accept you, compare the market you actually want to trade: its executable buy price, depth at your order size, trading and funding costs, and resolution conditions. A lower displayed probability alone does not establish better value.
Polymarket vs Kalshi at a glance
| What to compare | Polymarket.com | Kalshi |
|---|---|---|
| Eligibility | Geographic restrictions apply; check both residence and physical location. Separate US product excluded here. | Identity and country eligibility requirements apply; consult the Member Agreement. |
| Funding | Crypto-based funding; confirm supported assets, network and withdrawal route before sending funds. | Check available cash funding and withdrawal methods for your account and location. |
| Trading fees | Market-specific: do not assume every category is fee-free. Check the official fee documentation and market parameters. | Use the current fee schedule and order preview; costs depend on the contract and trade. |
| Market prices | Use a supported buy quote for the exact outcome, not a last trade or midpoint. | For binary contracts, Yes buy price is the Yes ask; No buy price is one minus the Yes bid. |
| Settlement | The written rules specify the source, end date and edge cases; resolution may involve an oracle process. | Read the individual contract rules and verification source before trading. |
| Liquidity | Inspect depth at your price and quantity; headline volume is not fillable liquidity. | Inspect depth at your price and quantity; headline volume is not fillable liquidity. |
Primary-source links below cover fees, restrictions and resolution. These summaries are research guidance, not an account-eligibility decision; official terms and the order preview take precedence.
Which has lower fees? Compare the whole trade
There is no reliable single fee percentage that answers this for every market. Polymarket's official documentation describes category-specific taker fees and fee-free markets. Kalshi publishes its own fee guidance. Check whether your order takes existing liquidity or provides it, and include costs outside the trading fee.
- Record the buy price for your intended quantity on each venue.
- Add the fee shown for that market and order type; do not assume a maker order will fill.
- Include any funding, network, withdrawal and currency-conversion charges that apply to your account.
- If you plan to exit before settlement, include the expected exit spread and any exit fees too.
Illustrative comparison, not live quotes or a venue fee schedule: a 45¢ buy price plus an assumed 2¢ of allocated costs is 47¢ all-in. A 46¢ buy price plus an assumed 0.5¢ of costs is 46.5¢ all-in. The lower headline price is not the lower total cost.
Why Polymarket and Kalshi odds can disagree
Different participants, funding routes, liquidity and fees can create genuine price differences. But apparently identical questions can also have different thresholds, deadlines, observation windows or resolution sources. Those are different contracts, not automatically an arbitrage opportunity.
For example, a contract asking whether Bitcoin touches a threshold at any time is not equivalent to one checking a closing price on a specific day. Likewise, an election winner is not necessarily the person later inaugurated. Read the rules before comparing the numbers.
Can you arbitrage between Polymarket and Kalshi?
Potentially, if both accounts are eligible and funded, the contracts have equivalent payout conditions, and the available opposite-outcome buy prices total less than the eventual payout after costs. Buying Yes on one venue and No on the other is a hedge only when the rules really align. A difference between two Yes prices is not itself locked-in profit.
PP compares supported source buy prices and applies matching and freshness safeguards. It does not execute both legs, guarantee fills, or certify identical legal settlement. Use the arbitrage guide for the worked example and the matching methodology for the evidence checks.
A practical decision checklist
- Confirm the platform and exact product accept you; never bypass geographic restrictions.
- Read the event, outcome, threshold, cutoff time and settlement-source rules.
- Check supported funding and withdrawals before depositing.
- Inspect executable buy prices and order-book depth at your intended size.
- Calculate total entry and exit costs, not just the headline price.
- Start with simulated practice if you are not ready for execution and settlement risk.
Frequently asked questions
Is Kalshi better than Polymarket?
Neither is universally better. Eligibility comes first; then compare the specific contract's funding requirements, all-in costs, buy-price depth and settlement rules.
Can US residents use Polymarket?
Do not confuse Polymarket.com with the separate Polymarket US product. Check the current geographic restrictions and the terms for the exact product; access to one is not permission to trade on the other.
Does Polymarket charge trading fees?
Some markets have taker fees and others are fee-free. Check official market-specific parameters and include intermediary or network costs where applicable; do not rely on a blanket no-fee claim.
Are the same markets available on both platforms?
Some events overlap, but market selection and contract rules differ. Matching titles alone cannot establish equivalent payouts.