The short version
| Kalshi | Polymarket US | |
|---|---|---|
| Regulator | CFTC (since 2020) | CFTC (since 2025) |
| Fee on $100 at 50¢ | $3.50 | $3.48 |
| If you wait for your price | No fee on most markets | You get a rebate |
| Minimum deposit | $10 | Not stated |
| PayPal and Venmo | Yes, fee after first deposit | Yes |
| Withdrawals | Free, debit card within hours | Free, 3–4 business days |
| Interest on balance | 3.50% APY over $250 | No |
| App Store / Google Play | 4.8 / 4.7 | 4.6 / 3.5 |
| Sign-up offer | Referral only | $25 for a $10 deposit, via some links |
| Our score | 4.4 / 5 | 3.8 / 5 |
Regulation
Both are proper US exchanges. Kalshi has been designated by the CFTC since November 2020 and clears trades through its own clearinghouse. Polymarket US runs on QCX LLC, designated in July 2025, with its own clearinghouse too. The thing to keep straight with Polymarket is that polymarket.com, the crypto site you may have heard about, is a separate international platform that the CFTC doesn’t regulate and that blocks US users.
Fees
The fees are close enough that they shouldn’t decide it for you. Both use a formula that charges the most at 50¢: Kalshi’s taker rate is 0.07 and Polymarket US’s is 0.0695, so a $100 trade at 50¢ costs $3.50 on Kalshi and $3.48 on Polymarket. The real difference is for people who set a price and wait. Kalshi charges those traders nothing on most markets, while Polymarket pays them a small rebate.
Markets
Kalshi has more. Alongside sports and politics it lists economics, finance, crypto, commodities, climate, culture, tech and “mentions” markets, plus perpetual futures. Polymarket US covers sports, politics, crypto, weather, tech, culture and economics. Both let you build combos, where all your picks have to win; Polymarket allows 2 to 10.
Money in and out
Kalshi takes $10 to start and almost every payment type, but card deposits cost up to 2% and PayPal and Venmo charge after your first deposit. Withdrawals are free, and debit card withdrawals usually land within hours. Kalshi also pays a variable 3.50% APY on balances of $250 or more.
Polymarket US takes debit card, ACH, Apple Pay, PayPal, Venmo, USDC and wire. Withdrawals are free but take 3 to 4 business days by card or bank. It doesn’t state a minimum deposit for card or bank.
Apps
Kalshi wins clearly on ratings: 4.8 on the App Store and 4.7 on Google Play, against Polymarket’s 4.6 and 3.5. If you’re on Android, that gap is worth paying attention to.
Which should you pick?
Pick Kalshi if you want the most markets, the best app and interest on idle cash. Pick Polymarket US if you place limit orders and want the rebate, or if you got a sign-up link with its $25 offer. Neither publishes a full list of states where it’s restricted, so check the app before you deposit.