Use the put-call parity calculator to solve missing European option values and check parity between call, put, strike price, stock price, rate, and time.
This put-call parity calculator helps you solve for one missing input in a European options pricing relationship. It is useful when you know the stock price, strike, interest rate, time to maturity, and one option premium, and want to check the implied value of the other side.
Use it to sanity-check market quotes, compare call and put prices with the discounted strike, and spot when an entered combination would violate basic no-arbitrage conditions.
$$C - P = S_0 - K e^{-rT}$$
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Put-Call Parity Calculator FAQ
It solves the European put-call parity relationship when one value is missing. You can use it to infer a call price, put price, strike, or stock price from the other inputs and check whether a quote set is internally consistent.
For European options on a non-dividend-paying stock, put-call parity is C - P = S_0 - K e^{-rT}. Rearranging that identity lets you solve for any one missing variable when the others are known.
A standard European call or put value should not be negative. If the implied result comes out below zero, the entered combination violates no-arbitrage logic, so the calculator treats the input set as invalid rather than displaying an impossible option price.
Not in the same exact equality form. The clean parity identity used here is for European options. American options can be exercised early, so they are typically described by bounds or inequalities instead of the exact equation used on this page.
You can enter time in days, months, or years. The calculator converts the selected unit to years internally before discounting the strike value.
The parity difference is (C - P) - (S_0 - K e^{-rT}). For a perfectly consistent European option input set, that value should be 0 apart from rounding. A non-zero result means the quoted values do not line up with exact parity.
It can help you spot parity inconsistencies, which may suggest a mispricing. In real markets, however, transaction costs, bid-ask spreads, funding assumptions, dividends, and exercise style all matter before treating a small difference as a usable arbitrage trade.
