Kalshi's taker fee is 0.07 × contracts × price × (1 − price), times the series multiplier (1 by default) and rounded up to the next cent, so it peaks at 1.75¢ per contract at a 50¢ price. Resting (maker) orders are free on standard series and pay a fee only on the series Kalshi lists with maker fees.
Kalshi's official fee formula, the per-series multiplier, when maker fees actually apply, cent rounding, fee-free markets and worked examples, checked against Kalshi's published fee schedule.
taker fee = round up( M × 0.07 × C × P × (1 − P) )
maker fee = round up( M_maker × 0.0175 × C × P × (1 − P) )
C is the number of contracts, P the price in dollars (a 50¢ contract is 0.50), and M the series' fee multiplier. M defaults to 1. Fee-free series carry a multiplier of 0, and Kalshi's public series API also reports 0.5 on some sports series. M_maker defaults to 0: on a standard series makers pay nothing. Maker fees apply only to the series listed under non-standard fees in the schedule, which the API flags as fee_type = quadratic_with_maker_fees. The schedule's table carries separate maker and taker columns: every listed series is 1 / 1 except the ten fee-free series (0 / 0) and the KXMVE combo markets (maker 2, taker 1). The public API exposes only the taker multiplier, so PolyKal keeps the maker column as a dated copy of the schedule.
Fees are rounded up to the next cent. The schedule's own fee table shows a single 50¢ contract charged $0.02 (theoretical $0.0175) and 100 contracts at 5¢ charged $0.34 (theoretical $0.3325). The formula's footnote says "rounded to a centicent" ($0.0001), which would give $0.3325 for that second order; the table itself settles the question: its first row charges $0.01 for a single 1¢ contract whose theoretical fee is $0.000693, which only whole-cent rounding explains. PolyKal follows the table.
| Order | Theoretical fee | Charged | Premium |
|---|---|---|---|
| 1 contract @ 50¢ | $0.0175 | $0.02 | +14% |
| 5 contracts @ 50¢ | $0.0875 | $0.09 | +3% |
| 10 contracts @ 10¢ | $0.0630 | $0.07 | +11% |
| 100 contracts @ 5¢ | $0.3325 | $0.34 | +2% |
Because every fee rounds up to a whole cent, the smallest orders carry a real premium over the formula. It shrinks quickly with size and is negligible above a few dozen contracts. An order that fills across several price levels is charged per fill, so each level rounds up separately; PolyKal's fill estimates apply the same per-level rounding, which can exceed a single whole-order rounding by up to one cent per extra level. The direction of the error is conservative.
The schedule effective 2026-07-07 lists these series with a multiplier of 0 for both takers and makers: KXBTCY, KXCITRINI, KXDOED, KXELECTIRAN, KXETHY, KXGAMBLINGREPEAL, KXGREENLAND, KXIRANDEMOCRACY, KXLAYOFFSYINFO and KXPAHLAVIHEAD. Treat this as a dated snapshot, not a live list: Kalshi can change a multiplier without republishing the PDF, and the public series API already reports values the PDF does not show (for example a 0.5 multiplier on a group of KXMLB baseball series). PolyKal's compare and event pages never use this list; they read the fee_multiplier returned by the series API for the specific market at the time of the estimate.
quadratic_with_combo_maker_fees.Kalshi's 0.07 taker rate equals Polymarket's crypto-category rate and is higher than every other Polymarket category: 0.05 categories are 29% cheaper, 0.04 categories 43% cheaper, and Polymarket's geopolitics markets are free. Makers pay nothing on Polymarket in every category, and nothing on Kalshi except on maker-fee series. Use the fee calculator for any size and price, or read the Polymarket fees breakdown.
A maker order is a limit order that rests in the order book and adds liquidity, waiting for another trader to fill it. Makers pay nothing on most Kalshi series and nothing at all on Polymarket.
A taker order fills immediately against a resting order, removing liquidity. Takers pay the trading fee on both Kalshi and Polymarket.
A resting order is a limit order sitting in the order book at your chosen price, unfilled until the market trades into it. Resting (maker) orders are the cheapest way to trade — free on most Kalshi series and on all of Polymarket.
The break-even probability is the win probability at which a trade neither gains nor loses after fees. Because you pay the after-fee fill price per contract but a winning contract is worth $1.00, your break-even equals that after-fee price read as a probability.
The after-fee fill price is the average price you actually pay per contract once the trading fee is added to the fill. Read as a probability, it is your break-even.
Kalshi charges takers 7% × contracts × price × (1 − price) per contract, rounded up to the next cent — at most 1.75¢ per contract, which occurs at the 50¢ price point. Makers pay nothing on standard series and 1.75% on the series Kalshi flags for maker fees. There are no settlement or membership fees. Verified against Kalshi's official fee schedule (effective 2026-07-07) as of 2026-09-12.
Takers pay a fee on every fill. Makers — resting limit orders that add liquidity — pay nothing on most series, and 1.75% only on the series Kalshi flags for maker fees. The fee is largest near a 50¢ price and shrinks toward 1¢ and 99¢. As of 2026-09-12.
On most Kalshi series, resting (maker) limit orders are free. Only series whose fee type is quadratic_with_maker_fees charge a maker fee, at 1.75% × contracts × price × (1 − price). Takers always pay. As of 2026-09-12.
Fee = round up to the next cent of ( M × 0.07 × C × P × (1 − P) ), where C is the number of contracts, P is the price in dollars from 0 to 1, and M is the series' fee multiplier (1 by default). A 100-contract taker order at 50¢ on a standard series costs 1.75. As of 2026-09-12.
You may quote this page with credit to “PolyKal” and a link to it. Market prices are third-party data from Polymarket and Kalshi.
The fee data on this page is also available as free, machine-readable JSON, with a verified_on date for every rate.
PolyKal Research. “Kalshi Fees Explained: Taker Fee Formula, Multipliers & Rounding.” PolyKal Research, updated 2026-10-10. https://polykal.net/kalshi-fees-explained/ (accessed the date you view this page).
Formula, rates, rounding and the fee-free list: Kalshi Fee Schedule (PDF, effective 2026-07-07). Per-series multipliers and maker-fee flags: Kalshi public Trade API, GET /trade-api/v2/series/{series_ticker}. Last checked 2026-09-03. Every rate and multiplier in one table, with a changelog and free JSON: fee schedule. Method details: methodology.
Independent tool. Not affiliated with, endorsed by, or operated by Polymarket or Kalshi. Data from public sources. Not financial advice.
Kalshi's taker fee is 0.07 × contracts × price × (1 − price), times the series multiplier (1 by default) and rounded up to the next cent, so it peaks at 1.75¢ per contract at a 50¢ price. Resting (maker) orders are free on standard series and pay a fee only on the series Kalshi lists with maker fees.
Kalshi's official fee formula, the per-series multiplier, when maker fees actually apply, cent rounding, fee-free markets and worked examples, checked against Kalshi's published fee schedule.
taker fee = round up( M × 0.07 × C × P × (1 − P) )
maker fee = round up( M_maker × 0.0175 × C × P × (1 − P) )
C is the number of contracts, P the price in dollars (a 50¢ contract is 0.50), and M the series' fee multiplier. M defaults to 1. Fee-free series carry a multiplier of 0, and Kalshi's public series API also reports 0.5 on some sports series. M_maker defaults to 0: on a standard series makers pay nothing. Maker fees apply only to the series listed under non-standard fees in the schedule, which the API flags as fee_type = quadratic_with_maker_fees. The schedule's table carries separate maker and taker columns: every listed series is 1 / 1 except the ten fee-free series (0 / 0) and the KXMVE combo markets (maker 2, taker 1). The public API exposes only the taker multiplier, so PolyKal keeps the maker column as a dated copy of the schedule.
Fees are rounded up to the next cent. The schedule's own fee table shows a single 50¢ contract charged $0.02 (theoretical $0.0175) and 100 contracts at 5¢ charged $0.34 (theoretical $0.3325). The formula's footnote says "rounded to a centicent" ($0.0001), which would give $0.3325 for that second order; the table itself settles the question: its first row charges $0.01 for a single 1¢ contract whose theoretical fee is $0.000693, which only whole-cent rounding explains. PolyKal follows the table.
| Order | Theoretical fee | Charged | Premium |
|---|---|---|---|
| 1 contract @ 50¢ | $0.0175 | $0.02 | +14% |
| 5 contracts @ 50¢ | $0.0875 | $0.09 | +3% |
| 10 contracts @ 10¢ | $0.0630 | $0.07 | +11% |
| 100 contracts @ 5¢ | $0.3325 | $0.34 | +2% |
Because every fee rounds up to a whole cent, the smallest orders carry a real premium over the formula. It shrinks quickly with size and is negligible above a few dozen contracts. An order that fills across several price levels is charged per fill, so each level rounds up separately; PolyKal's fill estimates apply the same per-level rounding, which can exceed a single whole-order rounding by up to one cent per extra level. The direction of the error is conservative.
The schedule effective 2026-07-07 lists these series with a multiplier of 0 for both takers and makers: KXBTCY, KXCITRINI, KXDOED, KXELECTIRAN, KXETHY, KXGAMBLINGREPEAL, KXGREENLAND, KXIRANDEMOCRACY, KXLAYOFFSYINFO and KXPAHLAVIHEAD. Treat this as a dated snapshot, not a live list: Kalshi can change a multiplier without republishing the PDF, and the public series API already reports values the PDF does not show (for example a 0.5 multiplier on a group of KXMLB baseball series). PolyKal's compare and event pages never use this list; they read the fee_multiplier returned by the series API for the specific market at the time of the estimate.
quadratic_with_combo_maker_fees.Kalshi's 0.07 taker rate equals Polymarket's crypto-category rate and is higher than every other Polymarket category: 0.05 categories are 29% cheaper, 0.04 categories 43% cheaper, and Polymarket's geopolitics markets are free. Makers pay nothing on Polymarket in every category, and nothing on Kalshi except on maker-fee series. Use the fee calculator for any size and price, or read the Polymarket fees breakdown.
A maker order is a limit order that rests in the order book and adds liquidity, waiting for another trader to fill it. Makers pay nothing on most Kalshi series and nothing at all on Polymarket.
A taker order fills immediately against a resting order, removing liquidity. Takers pay the trading fee on both Kalshi and Polymarket.
A resting order is a limit order sitting in the order book at your chosen price, unfilled until the market trades into it. Resting (maker) orders are the cheapest way to trade — free on most Kalshi series and on all of Polymarket.
The break-even probability is the win probability at which a trade neither gains nor loses after fees. Because you pay the after-fee fill price per contract but a winning contract is worth $1.00, your break-even equals that after-fee price read as a probability.
The after-fee fill price is the average price you actually pay per contract once the trading fee is added to the fill. Read as a probability, it is your break-even.
Kalshi charges takers 7% × contracts × price × (1 − price) per contract, rounded up to the next cent — at most 1.75¢ per contract, which occurs at the 50¢ price point. Makers pay nothing on standard series and 1.75% on the series Kalshi flags for maker fees. There are no settlement or membership fees. Verified against Kalshi's official fee schedule (effective 2026-07-07) as of 2026-09-12.
Takers pay a fee on every fill. Makers — resting limit orders that add liquidity — pay nothing on most series, and 1.75% only on the series Kalshi flags for maker fees. The fee is largest near a 50¢ price and shrinks toward 1¢ and 99¢. As of 2026-09-12.
On most Kalshi series, resting (maker) limit orders are free. Only series whose fee type is quadratic_with_maker_fees charge a maker fee, at 1.75% × contracts × price × (1 − price). Takers always pay. As of 2026-09-12.
Fee = round up to the next cent of ( M × 0.07 × C × P × (1 − P) ), where C is the number of contracts, P is the price in dollars from 0 to 1, and M is the series' fee multiplier (1 by default). A 100-contract taker order at 50¢ on a standard series costs 1.75. As of 2026-09-12.
You may quote this page with credit to “PolyKal” and a link to it. Market prices are third-party data from Polymarket and Kalshi.
The fee data on this page is also available as free, machine-readable JSON, with a verified_on date for every rate.
PolyKal Research. “Kalshi Fees Explained: Taker Fee Formula, Multipliers & Rounding.” PolyKal Research, updated 2026-10-10. https://polykal.net/kalshi-fees-explained/ (accessed the date you view this page).
Formula, rates, rounding and the fee-free list: Kalshi Fee Schedule (PDF, effective 2026-07-07). Per-series multipliers and maker-fee flags: Kalshi public Trade API, GET /trade-api/v2/series/{series_ticker}. Last checked 2026-09-03. Method details: methodology.
Independent tool. Not affiliated with, endorsed by, or operated by Polymarket or Kalshi. Data from public sources. Not financial advice.