Guide
What is a strike price in options trading?
A strike price is the fixed price at which an option contract can be exercised — the level at which a call buyer may buy, or a put buyer may sell, the underlying. On NSE, every Nifty or Bank Nifty option lists at a chosen strike, such as a 23,000 call. The strike never changes during the contract's life; it is the reference point against which the option's value and the trader's profit or loss are measured. It is a mechanical term, not a forecast.
How a strike price works
When you trade an option, you are choosing one specific price level out of many. A Nifty 23,000 call gives its buyer the right to buy Nifty at an effective 23,000, regardless of where the index actually trades. The 23,000 figure is the strike. The exchange lists a ladder of strikes around the current price — for Nifty these usually step in 50-point intervals, for Bank Nifty in 100-point intervals — so traders can pick the level that matches their view.
The strike is fixed for the life of the contract. What moves is the premium, the price you pay or receive for the option, which rises and falls as the underlying moves toward or away from the strike, as volatility changes, and as expiry approaches. Understanding that the strike is fixed while the premium floats is the first step to reading an option correctly.
In the money, at the money, out of the money
A strike is described by its position relative to the current price of the underlying. For a call, a strike below the current price is in the money (ITM), a strike near the current price is at the money (ATM), and a strike above it is out of the money (OTM). For a put, the labels reverse: strikes above the price are ITM and strikes below are OTM.
This matters because an option's premium splits into two parts. Intrinsic value is how far in the money the strike is — an OTM option has none. Time value is the rest of the premium, reflecting the chance the option finishes in the money before it expires. Far-OTM strikes are cheap precisely because they are pure time value and are likely to expire worthless.
Choosing a strike
The strike a trader picks expresses how much movement they expect and how much they are willing to pay. An ATM strike costs more but responds closely to the underlying; a far-OTM strike is cheap but needs a large move just to break even. Neither is inherently better — each is a different trade-off between cost and probability.
Liquidity is a practical filter. On NSE, strikes near the current price of Nifty and Bank Nifty trade heavily and have tight bid-ask spreads, while distant strikes can be thin and costly to enter or exit. Choosing an actively traded strike reduces the hidden cost of slippage, a point covered in our guides on the option chain and market depth.
Strike price and expiry
A strike does not exist in isolation — it is always paired with an expiry date. NSE lists weekly expiries for the headline index and monthly expiries across instruments, so the same 23,000 strike can exist for this week, next week and the monthly contract, each priced differently. The nearer the expiry, the faster time value decays.
On expiry day, the relationship between the strike and the closing settlement price decides the outcome. If a call's strike is below the settlement price it has intrinsic value and is settled accordingly; if it is above, it expires worthless. Index options in India are cash-settled, so no shares change hands — the difference is simply credited or debited.
Risk and the Indian context
Buying a far-OTM option because it is cheap is one of the most common ways new traders lose money. The low premium reflects a low probability of the strike being reached; most such options expire worthless, and the buyer loses the entire premium. The strike being affordable says nothing about whether it will be profitable.
This sits inside a sobering picture. According to SEBI's study released in September 2024, roughly 93% of individual F&O traders lost money in FY24, with aggregate losses exceeding 1.8 lakh crore rupees across FY22 to FY24. Understanding strikes is necessary mechanics, not an edge. Strike selection is a tool for expressing a tested view with defined risk, never a shortcut to returns.
Common Questions
Frequently Asked Questions
What does strike price mean in options?
+The strike price is the fixed price at which an option can be exercised. For a call it is the price the buyer can buy the underlying at, and for a put it is the price the buyer can sell at. The strike stays fixed for the whole contract, while the premium you pay moves as the underlying moves toward or away from it.
What is the difference between strike price and spot price?
+The spot price is the live market price of the underlying right now, such as the current level of Nifty. The strike price is the fixed level written into the option contract. The relationship between the two decides whether an option is in the money, at the money or out of the money, and how much intrinsic value it carries.
Which strike price is best for options trading?
+There is no single best strike. At-the-money strikes cost more but track the underlying closely, while out-of-the-money strikes are cheap but need a large move to become profitable and often expire worthless. The right strike depends on your view, your risk tolerance and the liquidity available, not on which premium looks cheapest.
What happens to the strike price on expiry day?
+On expiry the strike is compared with the settlement price of the underlying. A call finishes in the money if the settlement price is above its strike, and a put finishes in the money if the settlement price is below its strike. Index options in India are cash-settled, so the difference is credited or debited and out-of-the-money options expire worthless.
Do strike prices change during a contract?
+No. The strike price is fixed for the entire life of the option contract and does not move. What changes is the premium, the price of the option itself, which rises and falls with the underlying, with volatility and with the time left to expiry. The fixed strike is the reference point against which all of that is measured.