Put-call parity checker
Check whether a call and a put with the same strike and expiry are priced consistently with the share price and interest rates, and which side is dearer if they are not.
Runs entirely in your browserRuns entirely on your device — nothing you type is sent anywhere. Educational only, and not investment advice.
How to use this calculator
Each step names a control you will find on screen above.
- Share price
The current price of the underlying share or index.
- Strike
The common strike of the call and the put. Parity only holds between options with the same strike and expiry.
- Days to expiry
Calendar days until expiry, used to discount the strike to its present value.
- Call price and Put price
The market premiums of the two options — ideally mid-prices between bid and ask, taken at the same moment.
- Interest rate
The annual risk-free rate, such as a T-bill yield. The tool discounts the strike continuously: PV(K) = K × e^(−r × t).
Worked example: An at-the-money pair with a month to go
A share trades at ₹1,000. The ₹1,000 call costs ₹32 and the ₹1,000 put ₹24, with 30 days to expiry and a 7% interest rate. No dividend is due.
What to enter
- Share price
- ₹1,000
- Strike
- ₹1,000
- Days to expiry
- 30 days
- Call price
- ₹32
- Put price
- ₹24
- Interest rate
- 7%
What it shows you
- Call + PV(strike)
- ₹1,026.26
- Put + share
- ₹1,024.00
- Gap
- +2.26
- Call implied by parity
- ₹29.74
Where this is taught
A calculator gives you a number. These explain what the number means and when it misleads you.
- Technical Analysis11 minBlack-Scholes: what an option is actually worthThe formula that won a Nobel Prize and priced the options market. What its five inputs are, why volatility and time dominate, and why the model is a lens, not a crystal ball.
- Technical Analysis10 minPut-call parity: the equation that links every optionA call, a put, the stock and a bond are bound together by one no-arbitrage equation. What put-call parity says, how it pins option prices, and what a broken parity is really telling you.
- Technical Analysis12 minImplied volatility, and why premiums move without the stockImplied volatility is the market’s price for uncertainty, and it can move an option premium more than the stock does. It explains why an option gets dearer before results, and why buying it there so often disappoints.
- Market Basics8 minEquity savings funds: a little equity, a lot of cushionAn equity savings fund holds three things at once — equity, hedged arbitrage and debt — so that it qualifies for equity taxation while actually exposing you to only a fraction of the stock market’s swings. It is the calmest way to keep a toe in equities.
- Market Basics12 minFutures and options, explained honestlyWhat derivatives are, why they exist, how leverage actually works — and the SEBI data on what happens to retail traders who use them.