USA · Prediction markets · Free tool
Prediction market fee calculator
See what a trade really costs on Kalshi, Polymarket US, OG, Robinhood and ForecastEx: the fee, your break-even chance and the odds you actually get.
Prediction market fee calculator
All-in cost of this order
Fee 1.75¢/contract$51.75
$50.00 for the contracts plus $1.75 in fees
- Trading fee
- $1.75
- Fee per contract
- 1.75¢
- Payout if you’re right
- $100.00
- Profit if you’re right
- $48.25
- Loss if you’re wrong
- −$51.75
- Break-even chance
- 51.75%
- Odds you actually get, after fees (American · decimal)
- -107 · 1.93
The same order on every platform
| Platform | Fee | All-in | Break-even |
|---|---|---|---|
| Kalshi | $1.75 | $51.75 | 51.75% |
| Polymarket US | $1.74 | $51.74 | 51.74% |
| OG (Crypto.com) | $1.75 | $51.75 | 51.75% |
| Robinhood | $2.00 | $52.00 | 52.00% |
| Interactive Brokers (ForecastEx) | $1.00 | $51.00 | 51.00% |
Trading fees only, from each platform’s schedule as of September 30, 2026. Selling before settlement costs the fee again on that trade, and the bid-ask spread adds a cost no schedule shows.
How the calculator works
Pick a platform, enter the price of the contract in cents and how many contracts you’re buying, and say whether your order fills immediately (taker) or waits in the order book as a limit order (maker). The calculator applies that platform’s published fee schedule and shows what leaves your account, what you get back if you’re right, and the probability you need to be right just to break even. The table repeats the same order on the other four platforms in our ranking of the best US prediction markets.
Three of the five charge in proportion to price × (1 − price), so a 50¢ contract costs the most to trade and a 5¢ or 95¢ contract almost nothing. Robinhood adds a capped commission to the exchange fee, and Interactive Brokers charges a flat cent on ForecastEx. The full schedules, with deposit and withdrawal fees, are in our prediction market fees guide.
The fee schedules used
| Platform | Taker | Maker |
|---|---|---|
| KalshiKalshi exchange | 0.07 × contracts × price × (1 − price), rounded up to the next cent (at most 1.75¢ per contract) | Free on most markets |
| Polymarket USPolymarket US exchange | 0.0695 × contracts × price × (1 − price), rounded to the nearest cent (at most 1.74¢ per contract) | Rebate of 0.0125 × contracts × price × (1 − price), up to 0.31¢ per contract |
| OG (Crypto.com)Crypto.com's exchange (NADEX) | 0.07 × contracts × price × (1 − price) (at most 1.75¢ per contract), charged when you open and when you close | 0.0175 × contracts × price × (1 − price), up to 0.44¢ per contract |
| RobinhoodKalshi-listed contract through Robinhood | Commission of 10% × price × (1 − price) per contract (5% with Gold), capped at 1¢, plus a 1¢ exchange fee per contract | Same as taker |
| Interactive Brokers (ForecastEx)ForecastEx through IBKR | No commission; flat 1¢ exchange fee per contract on each side of a trade | Same as taker |
What 100 contracts cost
The fee on 100 contracts at three prices, as a taker and as a maker, calculated from the schedules above (Robinhood without Gold).
| Platform | Taker | Maker | ||||
|---|---|---|---|---|---|---|
| 20¢ | 50¢ | 90¢ | 20¢ | 50¢ | 90¢ | |
| Kalshi | $1.12 | $1.75 | $0.63 | $0.00 | $0.00 | $0.00 |
| Polymarket US | $1.11 | $1.74 | $0.63 | $0.20 rebate | $0.31 rebate | $0.11 rebate |
| OG (Crypto.com) | $1.12 | $1.75 | $0.63 | $0.28 | $0.44 | $0.16 |
| Robinhood | $2.00 | $2.00 | $1.90 | $2.00 | $2.00 | $1.90 |
| Interactive Brokers (ForecastEx) | $1.00 | $1.00 | $1.00 | $1.00 | $1.00 | $1.00 |
To turn a price into sportsbook-style odds, or to check whether a price is good value against your own estimate, see how to read prediction market prices as odds and our EV calculator.
Frequently asked questions
How are prediction market fees calculated?
Kalshi, Polymarket US and OG charge a fee per contract in proportion to price × (1 − price), which peaks at a 50¢ price: about 1.75¢ per contract on Kalshi and OG and 1.74¢ on Polymarket US. Robinhood adds a commission of up to 1¢ per contract to a 1¢ exchange fee, and Interactive Brokers charges a flat 1¢ per contract on ForecastEx with no commission. Our fees guide has every schedule.
What is the difference between a taker and a maker?
A taker fills an order that is already in the order book and pays the standard fee. A maker places a limit order that waits to be filled: most maker orders are free on Kalshi, earn a rebate on Polymarket US, and pay a quarter of the taker fee on OG. Robinhood and ForecastEx charge both the same.
What does “break-even chance” mean?
The probability you need to be right for the trade to break even after fees: your total cost divided by the $1-per-contract payout. Buying 100 contracts at 50¢ for $51.75 all-in on Kalshi needs the event to happen more than 51.75% of the time, which is the same as betting at about -107.
Does the calculator include deposit and withdrawal fees?
No, only trading fees. Bank transfers are free almost everywhere, but card and PayPal deposits, instant withdrawals and extra withdrawals can cost more than the trading fee; the fees guide lists them per platform.
Why do the odds after fees differ from the price?
Because the fee raises what you pay per contract. A 40¢ contract plus Kalshi’s 1.68¢ taker fee costs 41.68¢, which converts to about +140 rather than the +150 the bare price implies. The bid-ask spread in thin markets adds a further cost the calculator can’t see.
Keep reading
Sources
We verify facts against primary sources (regulators, court records, operators’ own terms) wherever possible.
- Fees — Kalshi , accessed 2026-09-30
- Kalshi Fees Explained (quoting the fee schedule effective 2026-07-07) — polykal.net , 2026-09-28
- Polymarket US fees (schedule effective 2026-09-25) — Polymarket US , accessed 2026-09-30
- Fees & Limits — OG.com , accessed 2026-09-30
- Robinhood Derivatives Standard Pricing Fee Schedule — Robinhood Derivatives, LLC , 2026-05-28
- Event contracts overview — Robinhood , accessed 2026-09-30
- IBKR Prediction Markets commissions — Interactive Brokers , accessed 2026-09-30
- ForecastEx regulatory information and fee schedule — ForecastEx , accessed 2026-09-30