Call and Put Options Explained for Beginners

What an option is

An option is a contract that gives the buyer a right, but not an obligation, to buy or sell an underlying asset at a fixed price (the strike price) on or before a fixed date (the expiry). In India, the most traded options are on indices such as NIFTY and BANKNIFTY, and on large stocks.

The buyer pays a price for this right, called the premium. The seller (also called the writer) receives the premium and takes on the obligation. Options trade in lots, so the money involved is the premium multiplied by the lot size.

Call options

A call option gives the right to buy at the strike price. Its value rises when the underlying rises. If NIFTY is at 24,000 and you buy a 24,000 call for ₹150, and at expiry NIFTY is at 24,400, the call is worth about 400 points. Your profit is roughly 400 - 150 = 250 points per unit, multiplied by the lot size.

If NIFTY ends at or below 24,000, the call expires worthless and the buyer loses the ₹150 premium. That is the maximum loss for a call buyer: the premium paid.

Put options

A put option gives the right to sell at the strike price. Its value rises when the underlying falls. Buy a 24,000 put for ₹140; if NIFTY ends at 23,700, the put is worth about 300 points and the profit is roughly 300 - 140 = 160 points per unit.

If NIFTY ends at or above 24,000, the put expires worthless and the buyer loses the premium. Puts are also used to protect a portfolio, a bit like insurance: the premium is the cost of protection.

ITM, ATM and OTM

At the money (ATM): strike closest to the current price. In the money (ITM): a call with a strike below the current price, or a put with a strike above it; it already has intrinsic value. Out of the money (OTM): a call with a strike above the current price, or a put below it; it has only time value.

OTM options are cheaper, which attracts beginners, but they need a larger move to become profitable and many expire worthless. ITM options cost more but move more closely with the underlying.

What makes up the premium

Premium = intrinsic value + time value. Intrinsic value is what the option would be worth if it expired right now. Time value is the extra amount paid for the chance that the price moves further before expiry.

Time value depends mainly on how much time is left and on implied volatility, the market's expectation of how much the price will move. As expiry approaches, time value shrinks, faster in the last few days. This decay is why buying options and simply waiting often loses money even when the price moves slightly in your favour.

Buying vs selling options

Option buyers have limited risk (the premium) and potentially large gains, but they need the price to move enough, soon enough, to beat time decay. Many bought options expire worthless.

Option sellers collect the premium and win if the price stays away from the strike, but their potential losses can be very large if the price moves sharply against them. Because of this, selling requires a much bigger margin deposit, often lakhs of rupees per lot for index options.

Neither side is free money. Buying has a lower win rate with occasional big wins; selling has a higher win rate with occasional big losses.

Choosing an expiry

Weekly options are cheap because little time is left, but that also means time decay is fast and the move must come quickly. Monthly options cost more and decay more slowly, giving an idea more time to work.

A useful habit is to match the expiry to the expected holding period with some room to spare. If you expect a move over the next week, an option expiring in two to three weeks gives the trade time without paying for months of time value.

Key risks for beginners

Leverage: a small premium controls a large notional value, so prices can change by 50-100% in a day.

Time decay: holding a bought option without a move costs money every day.

Liquidity: far OTM strikes and less popular stocks can have wide bid-ask spreads.

Expiry day: premiums can collapse or spike within minutes.

SEBI studies of F&O traders have repeatedly found that a large majority of individual traders lose money. Learning with virtual money first is a sensible step.

A worked example: buyer and seller of the same option

Suppose NIFTY is at 24,000 and the 24,200 call trades at ₹90 with five days left. Trader A buys one lot, Trader B sells one lot. The lot size is 75.

If NIFTY closes at expiry at 24,500, the call is worth 300 points. A gains (300 - 90) x 75 = ₹15,750; B loses the same amount. If NIFTY closes at 24,100, the call expires worthless: A loses ₹6,750, B keeps ₹6,750. If NIFTY spends the week near 24,000 the premium decays day by day, which is good for B and bad for A.

The same contract, two opposite risk profiles. Understanding both sides helps you see why a cheap option is not automatically a good one.

Practise options on iTradeChart

Open the option chain for NIFTY or any F&O stock to see calls and puts with premium, OI, IV and Greeks. You can buy or sell options in paper trading with realistic margin and charges, and use the strategy builder to see the payoff of combinations before placing them.

The Time machine has an options mode that replays a past day, so you can practise buying and selling calls and puts candle by candle, including the effect of time decay.