What this calculator does
Put-call parity works out checks or solves the no-arbitrage relationship between a call, a put and the underlying. Enter your own figures above and the answer updates as you type: nothing is fixed in the code, so the result reflects exactly the numbers you supply.
The formula this calculator evaluates is printed under the tool and explained below, so you can check the working by hand or reuse it in a spreadsheet.
The formula
FormulaC + PV(K) = P + S, where PV(K) = K / (1 + r)^t
The inputs explained
| Field | What to enter |
|---|---|
| Solve for | Choose from Call price, Put price, Spot price, Strike price (via PV). |
| Call option price ($) | A number, measured in your currency. Starts at 8. |
| Put option price ($) | A number, measured in your currency. Starts at 5. |
| Spot price of underlying ($) | A number, measured in your currency. Starts at 100. |
| Strike price ($) | A number, measured in your currency. Starts at 100. |
| Risk-free rate (%) | A number, measured in %. Starts at 3. |
| Years to expiry | A number. Starts at 2. |
Worked examples
Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.
How the answer changes with call option price
Every other input is held at the calculator’s starting values while call option price varies. Select any row to load that scenario into the calculator.