Prediction Market Fee Calculator
Compare fees across 9 platforms — find the cheapest place to trade
| Platform | Trading Fee | Settlement | Total Fee | Fee % | Net Profit | $/Contract | Relative |
|---|---|---|---|---|---|---|---|
Poly US | $0.05 | $0.00 | $0.05 | 0.10% | $49.95 | $0.0005 | |
Smarkets | $1.00 | $0.00 | $1.00 | 2.00% | $49.00 | $0.0100 | |
Poly Crypto | $1.75 | $0.00 | $1.75 | 3.50% | $48.25 | $0.0175 | |
Kalshi | $1.75 | $0.00 | $1.75 | 3.50% | $48.25 | $0.0175 | |
ForecastEx | $1.00 | $1.00 | $2.00 | 4.00% | $48.00 | $0.0200 | |
Betfair | $2.50 | $0.00 | $2.50 | 5.00% | $47.50 | $0.0250 | |
Robinhood | $2.00 | $2.00 | $4.00 | 8.00% | $46.00 | $0.0400 | |
Crypto.com | $2.00 | $2.00 | $4.00 | 8.00% | $46.00 | $0.0400 | |
PredictIt | $5.00 | $4.75 | $9.75 | 19.50% | $40.25 | $0.0975 |
| Price | Kalshi Taker | Kalshi Maker | Robinhood | Poly US |
|---|---|---|---|---|
| 5¢ | $0.34 | $0.09 | $2.00 | $0.005 |
| 15¢ | $0.90 | $0.23 | $2.00 | $0.015 |
| 25¢ | $1.32 | $0.33 | $2.00 | $0.025 |
| 35¢ | $1.60 | $0.40 | $2.00 | $0.035 |
| 45¢ | $1.74 | $0.44 | $2.00 | $0.045 |
| 55¢ | $1.74 | $0.44 | $2.00 | $0.055 |
| 65¢ | $1.60 | $0.40 | $2.00 | $0.065 |
| 75¢ | $1.32 | $0.33 | $2.00 | $0.075 |
| 85¢ | $0.90 | $0.23 | $2.00 | $0.085 |
| 95¢ | $0.34 | $0.09 | $2.00 | $0.095 |
- •Crypto example: taker fee = 0.07 × C × P × (1 − P); makers pay zero.
- •No Polymarket fee on withdrawals or profits; third-party charges may apply.
- •Other categories use different rates, including fee-free geopolitical markets. Check the market's official fee parameters.
- •0% maker fee, 0.10% taker fee
- •No withdrawal or settlement fee
- •Regulated DCM exchange
- •Taker: roundUp(0.07 × C × P × (1-P))
- •Maker: roundUp(0.0175 × C × P × (1-P))
- •Max taker at 50¢: 1.75¢/contract
- •2% deposit fee on debit card
- •50% fee reduction on S&P/Nasdaq
- •$0.01 commission + $0.01 exchange/side
- •Round-trip: ~$0.04 per contract
- •Routes to Kalshi exchange
- •10% fee on gross profits only
- •5% fee on all withdrawals
- •Effective: ~14.5-17.8% on profits
- •Position limit: $3,500/contract
- •$0.01/contract in spread
- •Commission-free via IBKR
- •~3.80% APY on collateral (offsets costs)
- •$1 contracts: $0.02 exchange fee/side
- •$10 contracts: $0.20 total/side
- •Flat fee regardless of probability
- •2%, 5%, or 8% on net winnings
- •Expert Fee: +20% (£25K-100K profit)
- •Expert Fee: +40% (£100K+ profit)
- •UK/International only
- •2% standard commission
- •1% pro tier (1,500+ bets or £1M+/mo)
- •3% select tier (£25K+ annual profit)
Why Fees Matter More Than You Think
On a 50¢ contract with a 55% true probability, your edge is only 5%. If fees eat 3% of that, you've lost 60% of your profit potential. For frequent traders, the difference between platforms can be thousands of dollars annually. Always factor in ALL fees — trading, settlement, deposit, and withdrawal.
Fee Model Types
Curve-based (Kalshi): Fees scale with P × (1-P), peaking at 50¢ and falling toward extremes. This means cheap contracts (5¢, 95¢) have very low fees, while 50/50 markets are most expensive.
Flat per-contract (Robinhood, ForecastEx): Same fee regardless of probability. Better for 50/50 markets, worse for extreme probabilities.
Profit-based (PredictIt, Betfair): Only charged when you win. Sounds good, but effective rates can exceed 15% when stacked with withdrawal fees.
Percentage-based (Polymarket US): A tiny fixed percentage (0.10%) on the contract premium. Generally the cheapest model.
Hidden Fees to Watch For
- •Kalshi charges 2% on debit card deposits — use ACH instead
- •PredictIt's 5% withdrawal fee stacks ON TOP of the 10% profit fee
- •No Polymarket fee on withdrawals or profits; third-party charges may apply.
- •Betfair's Expert Fee adds 20-40% for highly profitable users
- •Spread/slippage is an implicit fee not shown in fee schedules
How to Minimize Fees
- •Use maker orders when possible — Kalshi maker fees are 75% cheaper than taker
- •For 50/50 markets: flat-fee platforms (Robinhood) often beat curve-based (Kalshi)
- •For extreme probabilities (under 15¢ or over 85¢): curve-based is cheapest
- •ForecastEx pays 3.80% APY on collateral — this offsets fees for long-hold positions
- •Avoid PredictIt for large trades — the 10%+5% fee stack is brutal
Fee Impact on Break-Even
If a market trades at 50¢ and fees are 1.75¢ per contract, you need the true probability to be at least 51.75% to break even as a buyer. For a 10¢ contract with 0.63¢ fee, you need 10.63%. The lower the price, the smaller the absolute fee — but the higher the fee as a percentage of potential profit.
Your next step
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Expected value depends on the probability you enter. Explore prediction markets and consider fees and liquidity before interpreting an apparent edge.
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Results depend on your inputs and the assumptions shown by this calculator. Reference links explain the model; they do not supply a live price feed. Fees, execution and changing market conditions can affect actual outcomes.
Frequently asked questions
Which prediction market has the lowest fees?
Polymarket has the lowest effective fees — 0% trading fees, only a small spread. Kalshi charges event-based fees. PredictIt takes 10% of profits plus 5% withdrawal fee. Robinhood has no direct fees but wider spreads.
How do prediction market fees affect profitability?
Fees directly reduce your edge. A trade with 5% expected edge becomes unprofitable if total fees exceed 5%. Always calculate net returns after all platform fees, gas costs (for crypto platforms), and withdrawal fees.