Paste a market link to see the fill and fee estimate.
This free calculator gives the real cost of a Kalshi or Polymarket trade: the fee, the after-fee price per contract and the break-even probability, with no account needed. Rates are checked against each platform's official fee schedule and were last verified 2026-09-12.
Use this free Kalshi fee calculator and Polymarket fee calculator to see the real cost of a trade — taker and maker fees, after-fee fill price, and break-even — before you place it.
Fee schedule: formulas and ratesPaste a Kalshi or Polymarket market link and an amount — or enter a contract price and count yourself — and this tool returns the actual cost of the trade: the fee, and the after-fee fill price per contract. It's the number that matters before you place an order, not the quoted price.
Both Kalshi and Polymarket price trading fees with the same shape of formula — the fee rises toward a mid-price of 50¢ and shrinks toward the extremes — but the constants differ, and Polymarket varies its rate by market category while Kalshi uses one standard rate, adjusted per series, with most maker (resting) orders free. The calculator uses the figures verified against each platform's official fee schedule; the full breakdown with worked examples is in our Kalshi fees explained guide and its Polymarket counterpart.
It depends on the market. On crypto markets the taker rates match, so the difference comes down to spread and depth. On politics, Polymarket's rate is lower. For makers, the platforms are a category apart on the Kalshi series that charge maker fees, and close on the rest. The honest answer for any specific market is "run both and compare" — which is exactly what the compare page does with timestamped order-book snapshots.
fee = contracts × rate × price × (1 − price)
Both platforms charge a fee proportional to price × (1 − price), so the dollar fee peaks at 50¢ and shrinks symmetrically toward the extremes: a 5¢ or 95¢ contract carries roughly a fifth of the fee of a 50¢ contract on either platform. The most contested markets are the most expensive to trade.
Kalshi applies 0.07 for takers, multiplied by the series' fee multiplier (1 by default, 0 on fee-free series, 0.5 on some sports series per the public series API), and rounds each fee up to the next cent. Makers pay 0.0175 times a separate maker multiplier that only the fee schedule publishes: 1 on the series it lists, 2 on combo markets (KXMVE), 0 everywhere else. Polymarket applies a category rate to takers only, never charges makers, and rounds to 5 decimals.
| Category | Polymarket | Kalshi (standard series) | Difference | Result |
|---|---|---|---|---|
| Crypto | $1.75 | $1.75 | $0.00 | Identical; spread and depth decide |
| Sports / Economics / Culture / Weather / Other | $1.25 | $1.75 | $0.50 | Polymarket 29% lower |
| Politics / Finance / Tech / Mentions | $1.00 | $1.75 | $0.75 | Polymarket 43% lower |
| Geopolitics | $0.00 | $1.75 | $1.75 | Polymarket free |
Live check, 2026-10-12 20:44 UTC, across the 299 most-traded open events: the table shows Polymarket's published rate per category, but Polymarket sets the rate on each market, and the rates live markets declare in Polymarket's API don't all match it. Declared rates that differ from the table, or more than one declared rate: Sports: 5% on 100, 3% on 20 (e.g. Bills vs. Rams); Politics: 4% on 40, 0% on 1 (e.g. Tyler Robinson convicted of homicide?). Every sampled market declared the table's rate: Crypto 7%, Economics 5%, Culture 5%, Weather 5%, Other / General 5%, Finance 4%, Tech 4%, Mentions 4%, Geopolitics 0%. Counts are events in the sample. Paste a market link into the calculator to get that market's own rate. PolyKal re-checks this at least once a day. On-chain check, 2026-10-12 08:36 UTC: 49 real taker fills across 12 of 12 category/rate combinations were charged exactly what the declared rate implies.
| Category | Taker rate | Maker rate | vs. Kalshi's 0.07 |
|---|---|---|---|
| Crypto | 0.07 | 0 | Identical |
| Sports | 0.05 | 0 | 29% lower |
| Economics | 0.05 | 0 | 29% lower |
| Culture | 0.05 | 0 | 29% lower |
| Weather | 0.05 | 0 | 29% lower |
| Other / General | 0.05 | 0 | 29% lower |
| Politics | 0.04 | 0 | 43% lower |
| Finance | 0.04 | 0 | 43% lower |
| Tech | 0.04 | 0 | 43% lower |
| Mentions | 0.04 | 0 | 43% lower |
| Geopolitics | 0 | 0 | Free |
Live check, 2026-10-12 20:44 UTC, across the 299 most-traded open events: the table shows Polymarket's published rate per category, but Polymarket sets the rate on each market, and the rates live markets declare in Polymarket's API don't all match it. Declared rates that differ from the table, or more than one declared rate: Sports: 5% on 100, 3% on 20 (e.g. Bills vs. Rams); Politics: 4% on 40, 0% on 1 (e.g. Tyler Robinson convicted of homicide?). Every sampled market declared the table's rate: Crypto 7%, Economics 5%, Culture 5%, Weather 5%, Other / General 5%, Finance 4%, Tech 4%, Mentions 4%, Geopolitics 0%. Counts are events in the sample. Paste a market link into the calculator to get that market's own rate. PolyKal re-checks this at least once a day. On-chain check, 2026-10-12 08:36 UTC: 49 real taker fills across 12 of 12 category/rate combinations were charged exactly what the declared rate implies.
The schedule effective 2026-07-07 lists KXBTCY, KXCITRINI, KXDOED, KXELECTIRAN, KXETHY, KXGAMBLINGREPEAL, KXGREENLAND, KXIRANDEMOCRACY, KXLAYOFFSYINFO and KXPAHLAVIHEAD with a multiplier of 0. The list changes; check Kalshi's fee schedule or the market's series data before relying on a specific ticker being free. Select “Fee-free series” above to model one.
Yes — this one. Enter price and contracts and it returns the taker/maker fee, after-fee fill price and break-even for Kalshi (and Polymarket), using rates verified against each platform's official fee schedule. Rates last verified 2026-09-12.
Yes — this tool works for both platforms. Select Polymarket, enter the market category, price and number of contracts, and it returns the taker fee (makers are free on Polymarket), the after-fee fill price and break-even. Polymarket rates as of 2026-09-20; some categories are also confirmed against on-chain fee deductions.
Takers pay a fee on each trade; on most series, resting (maker) limit orders are free. The fee is largest near a 50¢ price and smaller toward the extremes. Enter your trade above to see the exact amount, or read the full breakdown in our Kalshi fees guide.
Polymarket charges takers a category-based rate (makers are free), so the real cost depends on the market's category and price. The calculator folds this into an after-fee fill price so you can compare it directly against Kalshi.
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 & Polymarket Fee Calculator.” PolyKal Research, updated 2026-10-10. https://polykal.net/tools/fee-calculator/ (accessed the date you view this page).
Kalshi Fee Schedule (PDF, effective 2026-07-07, last checked 2026-09-12) and Polymarket Help Center — Trading fees (updated 2026-07-10, last checked 2026-09-03). This calculator models the stated fee formula only; it does not model slippage from walking the order book. Use the compare page for book-aware estimates. The fee charged at execution on either platform is authoritative.
Independent tool. Not affiliated with, endorsed by, or operated by Polymarket or Kalshi. Data from public sources. Not financial advice.
Paste a market link to see the fill and fee estimate.
This free calculator gives the real cost of a Kalshi or Polymarket trade: the fee, the after-fee price per contract and the break-even probability, with no account needed. Rates are checked against each platform's official fee schedule and were last verified 2026-09-12.
Use this free Kalshi fee calculator and Polymarket fee calculator to see the real cost of a trade — taker and maker fees, after-fee fill price, and break-even — before you place it.
Fee schedule: formulas and ratesPaste a Kalshi or Polymarket market link and an amount — or enter a contract price and count yourself — and this tool returns the actual cost of the trade: the fee, and the after-fee fill price per contract. It's the number that matters before you place an order, not the quoted price.
Both Kalshi and Polymarket price trading fees with the same shape of formula — the fee rises toward a mid-price of 50¢ and shrinks toward the extremes — but the constants differ, and Polymarket varies its rate by market category while Kalshi uses one standard rate, adjusted per series, with most maker (resting) orders free. The calculator uses the figures verified against each platform's official fee schedule; the full breakdown with worked examples is in our Kalshi fees explained guide and its Polymarket counterpart.
It depends on the market. On crypto markets the taker rates match, so the difference comes down to spread and depth. On politics, Polymarket's rate is lower. For makers, the platforms are a category apart on the Kalshi series that charge maker fees, and close on the rest. The honest answer for any specific market is "run both and compare" — which is exactly what the compare page does with timestamped order-book snapshots.
fee = contracts × rate × price × (1 − price)
Both platforms charge a fee proportional to price × (1 − price), so the dollar fee peaks at 50¢ and shrinks symmetrically toward the extremes: a 5¢ or 95¢ contract carries roughly a fifth of the fee of a 50¢ contract on either platform. The most contested markets are the most expensive to trade.
Kalshi applies 0.07 for takers, multiplied by the series' fee multiplier (1 by default, 0 on fee-free series, 0.5 on some sports series per the public series API), and rounds each fee up to the next cent. Makers pay 0.0175 times a separate maker multiplier that only the fee schedule publishes: 1 on the series it lists, 2 on combo markets (KXMVE), 0 everywhere else. Polymarket applies a category rate to takers only, never charges makers, and rounds to 5 decimals.
| Category | Polymarket | Kalshi (standard series) | Difference | Result |
|---|---|---|---|---|
| Crypto | $1.75 | $1.75 | $0.00 | Identical; spread and depth decide |
| Sports / Economics / Culture / Weather / Other | $1.25 | $1.75 | $0.50 | Polymarket 29% lower |
| Politics / Finance / Tech / Mentions | $1.00 | $1.75 | $0.75 | Polymarket 43% lower |
| Geopolitics | $0.00 | $1.75 | $1.75 | Polymarket free |
Live check, 2026-10-12 20:44 UTC, across the 299 most-traded open events: the table shows Polymarket's published rate per category, but Polymarket sets the rate on each market, and the rates live markets declare in Polymarket's API don't all match it. Declared rates that differ from the table, or more than one declared rate: Sports: 5% on 100, 3% on 20 (e.g. Bills vs. Rams); Politics: 4% on 40, 0% on 1 (e.g. Tyler Robinson convicted of homicide?). Every sampled market declared the table's rate: Crypto 7%, Economics 5%, Culture 5%, Weather 5%, Other / General 5%, Finance 4%, Tech 4%, Mentions 4%, Geopolitics 0%. Counts are events in the sample. Paste a market link into the calculator to get that market's own rate. PolyKal re-checks this at least once a day. On-chain check, 2026-10-12 08:36 UTC: 49 real taker fills across 12 of 12 category/rate combinations were charged exactly what the declared rate implies.
| Category | Taker rate | Maker rate | vs. Kalshi's 0.07 |
|---|---|---|---|
| Crypto | 0.07 | 0 | Identical |
| Sports | 0.05 | 0 | 29% lower |
| Economics | 0.05 | 0 | 29% lower |
| Culture | 0.05 | 0 | 29% lower |
| Weather | 0.05 | 0 | 29% lower |
| Other / General | 0.05 | 0 | 29% lower |
| Politics | 0.04 | 0 | 43% lower |
| Finance | 0.04 | 0 | 43% lower |
| Tech | 0.04 | 0 | 43% lower |
| Mentions | 0.04 | 0 | 43% lower |
| Geopolitics | 0 | 0 | Free |
Live check, 2026-10-12 20:44 UTC, across the 299 most-traded open events: the table shows Polymarket's published rate per category, but Polymarket sets the rate on each market, and the rates live markets declare in Polymarket's API don't all match it. Declared rates that differ from the table, or more than one declared rate: Sports: 5% on 100, 3% on 20 (e.g. Bills vs. Rams); Politics: 4% on 40, 0% on 1 (e.g. Tyler Robinson convicted of homicide?). Every sampled market declared the table's rate: Crypto 7%, Economics 5%, Culture 5%, Weather 5%, Other / General 5%, Finance 4%, Tech 4%, Mentions 4%, Geopolitics 0%. Counts are events in the sample. Paste a market link into the calculator to get that market's own rate. PolyKal re-checks this at least once a day. On-chain check, 2026-10-12 08:36 UTC: 49 real taker fills across 12 of 12 category/rate combinations were charged exactly what the declared rate implies.
The schedule effective 2026-07-07 lists KXBTCY, KXCITRINI, KXDOED, KXELECTIRAN, KXETHY, KXGAMBLINGREPEAL, KXGREENLAND, KXIRANDEMOCRACY, KXLAYOFFSYINFO and KXPAHLAVIHEAD with a multiplier of 0. The list changes; check Kalshi's fee schedule or the market's series data before relying on a specific ticker being free. Select “Fee-free series” above to model one.
Yes — this one. Enter price and contracts and it returns the taker/maker fee, after-fee fill price and break-even for Kalshi (and Polymarket), using rates verified against each platform's official fee schedule. Rates last verified 2026-09-12.
Yes — this tool works for both platforms. Select Polymarket, enter the market category, price and number of contracts, and it returns the taker fee (makers are free on Polymarket), the after-fee fill price and break-even. Polymarket rates as of 2026-09-20; some categories are also confirmed against on-chain fee deductions.
Takers pay a fee on each trade; on most series, resting (maker) limit orders are free. The fee is largest near a 50¢ price and smaller toward the extremes. Enter your trade above to see the exact amount, or read the full breakdown in our Kalshi fees guide.
Polymarket charges takers a category-based rate (makers are free), so the real cost depends on the market's category and price. The calculator folds this into an after-fee fill price so you can compare it directly against Kalshi.
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 & Polymarket Fee Calculator.” PolyKal Research, updated 2026-10-10. https://polykal.net/tools/fee-calculator/ (accessed the date you view this page).
Kalshi Fee Schedule (PDF, effective 2026-07-07, last checked 2026-09-12) and Polymarket Help Center — Trading fees (updated 2026-07-10, last checked 2026-09-03). This calculator models the stated fee formula only; it does not model slippage from walking the order book. Use the compare page for book-aware estimates. The fee charged at execution on either platform is authoritative.
Independent tool. Not affiliated with, endorsed by, or operated by Polymarket or Kalshi. Data from public sources. Not financial advice.