Prediction Market Fee Calculator
Work out what Kalshi, Polymarket and Novig actually charge on a trade, and what you keep if it lands.
The same trade on every venue
| Venue | Fee | Profit if right | Return |
|---|---|---|---|
| Kalshi | $1.75 | $46.25 | +86.0% |
| Polymarket taker | $0.94 | $47.06 | +88.9% |
| Polymarket maker | $0.00 | $48.00 | +92.3% |
| Novig | $0.00 | $48.00 | +92.3% |
Kalshi uses its published formula, 0.07 × contracts × price × (1 − price), rounded up to the cent. Polymarket makers and Novig charge no commission — their cost is the bid-ask spread you cross, which no fee table captures.
How it works
Fees are the one cost in this category nobody advertises clearly. Kalshi publishes a formula rather than a rate, Polymarket charges a band that depends on the market category, and Novig charges nothing at all but takes its cut in the spread. That makes a like-for-like comparison hard to do in your head, which is what this calculator is for.
Kalshi's trading fee is 0.07 × contracts × price × (1 − price), rounded up to the next cent. The shape matters: the fee peaks on a 50¢ contract and shrinks toward either extreme, so a long shot at 3¢ costs almost nothing to trade while a coin-flip costs the most. Polymarket takes 0.75% to 1.80% of the position from takers and nothing from makers, who also collect rebates on some markets.
The comparison table runs your exact trade through every venue at once. For the detail behind each schedule, see our Kalshi fees explainer and Polymarket fees explainer.
Frequently asked questions
How much does Kalshi charge per trade?
The published formula is 0.07 × contracts × price × (1 − price), rounded up to the cent — about $1.75 on 100 contracts at 50¢. It is highest near 50¢ and falls away toward either extreme.
Does Polymarket charge a fee?
Takers pay 0.75–1.80% by category; makers pay nothing and collect 20–50% rebates on some markets. On top of that sit gas on Polygon and whatever your USDC on-ramp charges.
Which prediction market has the lowest fees?
Novig charges nothing, which makes it cheapest on paper — see our Novig review. But a zero-fee venue with a wide book can cost more than a small fee on a tight one, because the spread you cross is a real cost no fee table shows.
Other calculators
For live prices instead of hypotheticals, see the Polymarket vs Kalshi arbitrage scanner, or compare the venues in our head-to-head breakdown.
