Lot Size

What it is

In the derivatives market you don't trade one share or one index unit at a time — you trade in standardised bundles called lots. The lot size is the fixed number of units in one contract, set by the exchange for each underlying. For example, one Nifty option lot is currently 75 units, and one Bank Nifty lot is 30 units. So the smallest position you can take is one lot, and you scale up in whole multiples.

Why it exists

Standardising lot sizes makes contracts uniform, liquid and easy to trade, and ensures each F&O position has meaningful size — derivatives are leveraged, professional-grade instruments, not meant for buying a single share's exposure. The contract value equals lot size × price, which is why one Nifty lot represents a large rupee amount.

In India

SEBI revised the rules in late 2024 to curb excessive retail speculation, raising the minimum contract value to roughly ₹15–20 lakh at the time a contract is introduced. The exchange then sets each lot size so the contract value stays in that band, and revises it periodically as the index level changes (Nifty's lot, for instance, has been adjusted to keep value in range). Stock F&O lots vary widely by company.

Common mistakes

New traders underestimate how much capital and risk one lot carries — because of leverage, a small adverse move in a single Nifty lot can mean large rupee losses and margin calls. Others forget that lot sizes change over time and across stocks, so they must check the current size before trading. Always calculate the full contract value and the worst-case rupee loss for even one lot before entering, and size positions to your actual capital and risk appetite — not to the temptation of cheap-looking premiums or the lure of controlling a large position with little money. One lot is the floor, not a small bet.