Polymarket vs Kalshi
Last updated · how we verify
Polymarket and Kalshi charge fees the same way, and Polymarket charges less.
Both use coefficient × price × (1 − price). Kalshi's coefficient is 0.07 across the
board — equal to Polymarket's most expensive category — while Polymarket's Politics markets
are 0.04, Geopolitics is free, and
makers pay nothing and earn rebates. The real reasons to choose Kalshi are that it is
custodial, fiat-funded, and has a desktop web platform, which Polymarket US does not.
Kalshi is US-only.
Fees: the same formula, different inputs
This is the part almost every comparison gets wrong. Both platforms charge a fee shaped by
coefficient × price × (1 − price). Neither charges a flat percentage.
| Polymarket | Kalshi | |
|---|---|---|
| Formula | fee = shares × feeRate × price × (1 − price) | fee per contract = ceil(0.07 × price × (1 − price) × 100) / 100 |
| Taker coefficient | 0 to 0.07, by category | 0.07 |
| Peak taker fee / 100 | $0.00–$1.75 | ≈$1.75 |
| Maker fee | $0 — makers are never charged | Roughly ¼ of the taker rate |
| Maker rebates | 20–25% | None |
| Free categories | Geopolitics | None |
| Rounding | 5 decimal places | Rounded up per contract to the cent |
Two structural advantages for Polymarket fall out of that table. Its cheapest categories are much cheaper — Politics at 0.04 is roughly half Kalshi's coefficient, and Geopolitics is free. And the maker side is not merely cheaper but negative: Kalshi charges makers, Polymarket pays them.
Kalshi rounds each contract's fee up to the nearest cent. On small positions at extreme prices that rounding can dominate the arithmetic, because the true fee is a fraction of a cent but you still pay one. Polymarket rounds to five decimal places, so small trades are charged closer to the true amount.
Source: help.polymarket.com, thelines.com · verified 17 August 2026
Exact per-category multipliers unconfirmed. State only the standard 0.07 formula; do not publish per-category multiplier values.
Everything else
| Polymarket | Kalshi | |
|---|---|---|
| Who can use it | Global, except the blocked list. US residents use Polymarket US. | US only |
| Regulator | Polymarket US: CFTC DCM. International: offshore, non-custodial. | CFTC DCM |
| Custody | Non-custodial (intl) — your keys | Custodial — Kalshi holds member funds |
| Funding | USDC on Polygon, or card on-ramp | Fiat: bank transfer, debit card, and crypto deposits |
| Desktop web | Yes internationally; no on Polymarket US | Yes |
| KYC | Not on the international exchange; required on Polymarket US | Required |
| Market breadth | Very wide | Narrower, strong on economics and US politics |
| Volume | $10.57 billion (March 2026) | Materially lower |
| Resolution | UMA Optimistic Oracle | Exchange rules under CFTC oversight |
| State disputes | 7 states litigating | Same disputes; criminal charges filed in Arizona |
Availability varies by jurisdiction. 18+. Event contracts carry risk of loss.
You appear to be in the US. Polymarket’s international exchange blocks US IP addresses — use Polymarket US, the CFTC-regulated exchange, instead. See what’s available in your state.
Verdict
Pick Polymarket if you are outside the US, if you post limit orders, if you trade politics or geopolitics, or if you want to hold your own funds.
Pick Kalshi if you are in the US and want desktop web access today, or if you specifically want a custodial fiat account with password recovery and no crypto involved. Kalshi genuinely wins the US desktop case, because Polymarket US has no web platform.
Both face the same 7-state legal dispute, so state risk is not a differentiator. Check your state →
Questions
Does Kalshi charge 7% fees?
No, and this is a widespread misreading. The old site claimed a flat '7% fee' for Kalshi. That is wrong — 0.07 is a coefficient in a price-weighted formula, not a 7% charge. At a 50c contract the fee is about $1.75 per 100 contracts, i.e. ~1.75% of notional.
Which is cheaper, Polymarket or Kalshi?
Polymarket, in almost every case. Kalshi's 0.07 coefficient equals Polymarket's most expensive category (Crypto); Polymarket's Politics markets are 0.04 and Geopolitics is free. Polymarket also charges makers nothing and pays rebates, whereas Kalshi charges makers roughly a quarter of the taker rate.
Can I use Kalshi outside the US?
No. Kalshi is US-only. If you are outside the US, Polymarket's international exchange is the realistic option and Kalshi is not a substitute.
Which is safer?
Different risks rather than different amounts. Kalshi is custodial and CFTC-regulated — you are protected against your own key loss but exposed to normal account controls. Polymarket's international exchange is non-custodial — nobody can freeze your funds, and nobody can recover them. Full analysis.
Which has more markets?
Polymarket, by a wide margin, and more volume behind them — $10.57 billion in March 2026. Kalshi's list is narrower but well covered in economics and US politics.
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Polymarket US
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All figures on this page verified 17 August 2026 against primary sources where reachable. Unconfirmed values are marked.