Prediction Market Calculator - Contract Value

For Kalshi, Polymarket, and Robinhood Prediction Markets

Plan and evaluate your prediction market positions before you commit. Enter the cost and price for each contract on Kalshi, Polymarket, Robinhood, or any other prediction market platform. The calculator shows your potential payout and profit for each contract after fees, and totals your planned exposure across all positions. Check which contracts you intend to buy and which you expect to win to see your projected P&L.

Cost ($) Price (0–1) Fee Payout Profit Correct?
Total Cost $0.00
Total Payout $0.00
Total Profit $0.00

How the Calculator Works

Enter Your Contracts

Add a row for each position. Enter the total cost (how much you're spending), the price per share (e.g. 0.65 for a 65¢ contract), and the platform fee (defaults to 1%).

Payout Formula

Payout is calculated as (cost / price) × (1 − fee). This is your projected net return if the prediction resolves in your favor. Profit is payout minus your planned cost.

Track Your Positions

Use the first checkbox on each row to mark which contracts you plan to buy. Unchecked rows are excluded from the total cost. Use the Correct? checkbox to mark which predictions you expect to win, included in total payout.

Batch Operations

Click a row to select it, shift-click to select a range, or Ctrl/Cmd+click to add individual rows. Toggle a checkbox or edit the fee on any selected row to apply the change to all selected rows at once.