Break-Even Win Rate Calculator
Enter a contract price and platform to see how often you need to be right just to break even. Fees shift the threshold higher than you might think.
Break-Even Calculator
Contract price
Platform
You need to be right
60.5%
of the time to break even
Why Breakeven Matters
A contract trading at 60 cents doesn't just need a 60% chance of happening to be worth buying. Platform fees shift the breakeven probability upward. On Polymarket, the 2% fee on winnings pushes a 60-cent contract's breakeven to about 60.5%. On Kalshi, taker fees can push it past 62%. That difference matters when you're looking for edges measured in single-digit percentages.
How Platform Fees Affect Your Edge
Your “edge” on a prediction market trade is the gap between your estimated true probability and the breakeven probability — not the contract price. If you think an event has a 70% chance and the contract is at 65¢, your gross edge is 5%. But after Kalshi taker fees, the breakeven shifts from 65% to roughly 66.5%, cutting your real edge to 3.5%. On a $500 position, that's $7.50 less profit than you thought. Over hundreds of trades, ignoring fees means systematically overestimating your edge.
How to Use This Calculator
- Enter the contract price (e.g., 60¢ for a “Yes” contract)
- Select your platform — Polymarket Global, Polymarket US, Kalshi Taker, Kalshi Maker, or Custom
- The calculator instantly shows your breakeven win rate after fees
- Compare that breakeven against your probability estimate to see your true edge
Worked Example
You see “Will the Fed cut rates in June?” trading at 45¢ on Kalshi. Without fees, you need a 45% true probability to break even. As a Kalshi taker, the fee is 7% × 0.45 × 0.55 = 1.73¢ per contract. Your effective cost per contract is 46.73¢, pushing breakeven to about 46.7%. If your model says 50%, your real edge is 50% - 46.7% = 3.3%, not 5%. On Polymarket Global, the same contract's breakeven would be about 45.6% (2% of the 55¢ profit = 1.1¢ fee), giving you a 4.4% edge instead.
Fee Impact Comparison by Contract Price
| Contract Price | Polymarket Global | Kalshi Taker | Kalshi Maker |
|---|---|---|---|
| 20¢ | 20.3% | 21.1% | 20.3% |
| 35¢ | 35.5% | 36.6% | 35.4% |
| 50¢ | 50.5% | 51.8% | 50.4% |
| 65¢ | 65.4% | 66.6% | 65.4% |
| 80¢ | 80.3% | 81.1% | 80.3% |
Kalshi taker fees have the biggest impact near 50¢ contracts. For extreme-odds contracts (10¢ or 90¢), the fee difference between platforms shrinks substantially. Always check the breakeven at your specific price point rather than relying on general rules. For a deeper fee breakdown, use our Prediction Market Fee Calculator. Once you know your real breakeven, check whether a trade is worth it with the Prediction Market EV Calculator.
Common Questions
Why is breakeven different from the contract price?
Because platforms charge fees. Even though you buy a contract at 60 cents and it pays $1 if you win, the fee reduces your effective payout. You need to win more often than 60% of the time to cover both the cost of the contract and the fees.
Which platform has the lowest fee impact?
Polymarket US has the lowest fees (0.10% taker fee), followed by Polymarket Global (2% on winnings), then Kalshi maker (1.75% formula), then Kalshi taker (7% formula). The impact varies by contract price — Kalshi's formula hits hardest around the 50-cent mark.
How should I use this?
Before buying any contract, check the breakeven. If you think an event has a 65% chance and the contract is at 60 cents, your edge is only 5% before fees. After fees, it might be closer to 3-4%. Know your real edge, not just the gross number.
How much does Kalshi charge in fees?
Kalshi uses a formula-based fee: 7% × price × (1 - price) for takers and about 1.75% × price × (1 - price) for makers. This means fees peak on 50/50 markets (~1.75¢ per contract for takers) and shrink toward zero for extreme-odds contracts. On a 50¢ contract, a taker pays about 1.75¢ in fees.
How much does Polymarket charge in fees?
Polymarket Global charges 2% on net winnings only — you pay nothing extra if you lose. Polymarket US charges a much lower 0.10% taker fee. For a winning trade where you bought at 60¢ and received $1.00, the Global fee is 2% of your 40¢ profit = 0.8¢ per share.
Do prediction market fees affect the breakeven the same at all prices?
No. Kalshi's fee curve peaks at 50¢ contracts and drops toward zero at extreme prices. At 10¢ or 90¢ contracts, Kalshi fees are very small. Polymarket's 2% fee has a consistent impact across all prices — but it's proportional to winnings, so it matters more when profit per share is small (high-probability contracts).