Hedge & Arbitrage Calculator

Size a two-leg arbitrage from your budget, or find the hedge that locks in a position you already hold.

What do you want to do?

Polymarket fee

Kalshi leg price

Polymarket leg price

Budget ($)

Contracts per leg1041

Total cost$999.36

Fees (Kalshi + Polymarket)$30.95

Locked-in profit (if both legs fill)$10.69

ROI1.04%

✅ Both outcomes pay a profit after fees

Buy the same number of contracts of YES on one platform and NO on the other; exactly one pays $1.00 per contract at resolution. Kalshi taker fee is 0.07 × price × (1 − price) per contract, rounded up to the cent. Assumes full fills at the quoted prices. Not financial advice.

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How a hedge works on prediction markets

A binary contract pays $1.00 if it is right and $0 if it is wrong. If you hold YES at 40¢ and the market later offers NO at 50¢ somewhere else, buying NO makes one side always pay out. Size the two legs so both outcomes pay the same and the result no longer depends on the event.

Whether that result is a profit depends on the prices: the YES you hold and the NO you buy together cost less than $1.00 only when the two prices add to less than 1 after fees. Above that, the hedge locks in a loss, which can still beat an unhedged position if you want out of the risk.

Hedge versus arbitrage

A new arbitrage is a hedge you open on purpose: both legs at once, from a spread you spotted. A hedge on an open position is the same math started from a leg you already own. Both use the fees of each venue: Kalshi's per-order taker fee and Polymarket's share of net winnings.