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Every Kalshi trade can carry a fee, and over a year of active trading those fees add up. They also lower your taxable gain, so leaving them out means paying tax on money you never kept.
How Kalshi calculates trading fees
For most markets, Kalshi's published fee formula has been:
Because the formula multiplies the price by one minus the price, fees are largest for contracts priced near 50¢ and shrink toward zero near 1¢ or 99¢. Kalshi sets different rates for some markets and changes its schedule from time to time, so check its current fee page for exact numbers.
| Trade | Cost | Fee |
|---|---|---|
| 100 contracts at 50¢ | $50.00 | $1.75 |
| 100 contracts at 90¢ | $90.00 | $0.63 |
| 100 contracts at 10¢ | $10.00 | $0.63 |
A $1.75 fee on a $50 position is 3.5% of what you put in. On short, frequent trades near 50¢, fees can take a real share of your profit.
How fees affect your taxes
Trading fees are a cost of the trade. They reduce your gain, or increase your loss, on the position they belong to. Say you make $12.00 on a trade and paid $1.75 in fees along the way. Your taxable gain is $10.25, not $12.00.
That sounds small, but across hundreds of trades it isn't. A trader who pays $1,500 in fees over a year and forgets them overstates their gain by $1,500. In the 24% bracket, with 60/40 treatment, that's roughly $280 of tax on money they never kept.
Check fees are counted once
The opposite mistake happens too. If your records already show P&L after fees, and you subtract fees again, you understate your gain. Before filing, make sure you know whether each number you're using is gross or net of fees.
For how the net figure is taxed, read How Kalshi trades are taxed.
This guide is general information, not tax advice. Tax treatment of event contracts is still evolving, so confirm how it applies to you with a tax professional.