A call option gives you the right to buy an asset at a fixed price (strike price) by a certain date. You pay a premium for this right. If the stock rises above the strike price, your call becomes profitable. If it does not, you lose only the premium paid — your maximum loss is capped.
Example: You buy a call on Reliance at a Rs 2,500 strike price for Rs 50 premium. If Reliance rises to Rs 2,700, your option is worth Rs 200 — a 300% return on your Rs 50 investment. If Reliance stays below Rs 2,500, the option expires worthless. Break-even point: Rs 2,550 (strike + premium).
Call options are used for: speculation (leveraged bet on price increase), income generation (selling covered calls on stocks you own), and hedging (protecting short positions). The call-put parity theorem connects call and put prices mathematically. In India, NSE options expire weekly (for Nifty/Bank Nifty) and monthly for individual stocks.