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Polymarket & Kalshi Profit and Payout Calculator

Calculate prediction-market payouts, fees, net profit, ROI and break-even for settlement or an early sale.

FREE SCENARIO TOOL

What would this trade pay?

Choose the outcome you buy. Its price is entered directly, including for NO.

Contract spend excludes fees. Use your expected average fill price to account for slippage. Kalshi estimates use whole contracts (fractional execution is outside this estimate); venue rounding and split fills can differ. Use manual fees for special schedules.

NET PROFIT / LOSS

$147.00

142.72% return on total outlay

Shares / contracts
250
Contract cost
$100.00
Entry fee
$3.00
Exit fee
$0.00
Other costs
$0.00
Gross payout / sale proceeds
$250.00
Total initial outlay
$103.00
Maximum loss on losing settlement
$103.00
Settlement break-even probability
41.20%

Preview updates as you type. This is a cost estimate, not a forecast of the outcome.

Schedule references checked 2026-09-29: Polymarket fees · Kalshi fee formula · Kalshi rounding by member type · Kalshi current market exceptions. Fees can change. Estimates assume one fill per leg and exclude taxes and rebates. The calculator does not place trades.

How the payout calculation works

For a binary contract paying $1 when your outcome wins, gross settlement payout equals the number of shares you hold. Net profit subtracts the purchase cost, entry fee and other costs. An early sale uses the exit price and also subtracts any exit fee. A losing outcome pays zero.

Worked example: buy 100 shares at 40¢, using the Polymarket international 0.05 coefficient. Contract cost is $40 and the single-fill entry fee is $1.20. If your outcome wins, gross payout is $100 and net profit is $58.80 on $41.20 of total outlay. If it loses, the loss is $41.20. The settlement break-even probability is 41.2%.

A price is not a promised return

A 40¢ contract suggests a market-implied probability near 40%, before frictions. It does not mean you earn 40%. The calculator models a purchased binary position; it does not model short sales, leveraged products, combos, taxes or rebates. Buying NO uses the quoted NO price directly.

Kalshi’s API documentation distinguishes direct-member balances ($0.0001 precision) from non-direct or FCM balances ($0.01 precision). Select the matching account type, or enter the actual quoted fees manually. This is a single-fill estimate: it does not model the rounding accumulator across split fills. Series multipliers, fee overrides and intermediaries can change the charge.