What Is Lot Size in F&O (Futures and Options)?
In India's derivatives market, you don't trade a single share of a future or option — you trade a fixed bundle called a lot. The lot size is the number of underlying shares (or index units) in one contract.
Why the exchange sets lot size
The NSE fixes a lot size per contract so each contract has a roughly standardised notional value. As a stock's price changes a lot over time, the exchange revises lot sizes periodically to keep contract values in a sensible band.
How it affects your capital
Because you must trade at least one full lot, F&O requires more capital than buying a single share. If an index lot is 75 units and the index is at 24,000, one futures contract represents a notional 75 × 24,000 = ₹18 lakh — though you post only margin, not the full amount. This is why F&O carries leverage and risk.
Finding the lot size
Lot sizes are published by the exchange and change over time, so always check the current contract specification before trading. For the cash-market basics first, see intraday vs delivery and open interest.