Put-Call Parity Calculator

Check the theoretical relationship between a European call, a European put, the spot price, and the discounted strike. This page also keeps the formula, examples, FAQs, and references close by so you can check the result with confidence.

What This Put-Call Parity Calculator Helps You Do

Put-call parity says call price plus present value of the strike should equal put price plus spot price. Review the formula and examples below if you want to see how the result is derived.

This page is meant to give you a fast answer, but it also helps you double-check the math before you make a decision. Start with the inputs that you already know, run the calculation, and then compare the output with the formula, examples, and FAQs below so you can see whether the answer fits the situation you are modeling.

If the result looks off, the usual causes are a unit mismatch, a missing decimal, the wrong scenario, or a value that needs to be entered as a rate instead of a total. The notes on this page are designed to make those checks easy without forcing you to leave the calculator and search for context elsewhere.

  • Use the calculator first for a quick estimate.
  • Use the formula to understand how the result is built.
  • Use the examples to compare common use cases.
  • Use the references when the answer depends on a standard or assumption.

Common Checks

A quick result is useful, but the best result is one that still makes sense when you look at it a second time. If you are comparing scenarios, try changing one input at a time so you can see which variable has the biggest impact on the final answer. That makes it much easier to spot whether the calculation matches your expectations.

It also helps to keep the context of the problem in mind. A calculator can tell you the math, but you still need to decide whether the input represents a total, a rate, an average, or a category-specific assumption. When in doubt, start with a simple example from the page and scale up from there.

  • Check that every unit matches the rest of the problem.
  • Keep rates, totals, and averages separate.
  • Adjust one variable at a time when testing scenarios.
  • Use the smallest realistic input first, then scale upward.

Scenario Planning

This calculator is especially useful when you want a quick answer before you commit time, money, or effort. Try one baseline input set, then change a single number and compare the result so you can see how sensitive the answer is to that variable.

That makes the page useful for more than just arithmetic. It becomes a small decision aid that helps you compare options, test assumptions, and explain the final number with confidence when you need to share it with someone else.

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Result

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Quick Answer: Put-call parity says call price plus present value of the strike should equal put price plus spot price. Review the formula and examples below if you want to see how the result is derived.

How to Calculate Put-Call Parity Calculator

  1. Enter the option prices: Provide the call and put prices.
  2. Enter the spot and strike prices: Use the underlying asset price and strike price.
  3. Enter rate and expiry: Discount the strike using the risk-free rate and years to expiry.

Put-Call Parity Calculator Formula

C + PV(K) = P + S
Variable Meaning Unit
C European call price $
P European put price $
PV(K) Present value of the strike price $
S Spot price of the underlying asset $

Worked Examples

USA - Parity gap
  • Call price: $12
  • Put price: $8
  • Spot price: $100
  • Strike price: $100
  • Risk-free rate: 5%
  • Years to expiry: 1

Result: $8.00

A positive gap suggests the inputs do not satisfy parity exactly.

UK - Solve for call
  • Call price: $12
  • Put price: $8
  • Spot price: $100
  • Strike price: $100
  • Risk-free rate: 5%
  • Years to expiry: 1

Result: $12.76

The implied call price can be derived from the other three values.

EU - Present value of strike
  • Call price: $12
  • Put price: $8
  • Spot price: $100
  • Strike price: $100
  • Risk-free rate: 5%
  • Years to expiry: 1

Result: $95.24

Discounting the strike shows how much it is worth today.

How to Interpret Your Results

Range Meaning Action
Near zero gap The inputs are close to parity Check the spread for rounding differences.
Positive gap Call plus discounted strike is above put plus spot Look for a pricing inconsistency or arbitrage opportunity.
Negative gap Put plus spot is above call plus discounted strike Check whether one of the inputs needs to be adjusted.

Frequently Asked Questions

The classic parity relationship is for European options.

Because the strike is paid or received at expiry, not today.

A nonzero gap suggests the inputs are not in theoretical equilibrium.
Planning note: This calculator is a theoretical model for European options and not a trading recommendation.

References

Last reviewed: April 2026