Glossary · Options
Lot Size
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Lot size is the fixed number of units of the underlying that one futures or options contract represents — the minimum quantity you can trade in that contract. In NSE derivatives you cannot buy 10 units of a NIFTY option; you trade in whole lots. As of 2026 the NIFTY lot size is 75 and the BANKNIFTY lot size is 35; stock F&O lots vary by stock. Exchanges revise lot sizes periodically to keep contract values within regulatory bands, so always confirm against the latest NSE contract specifications.
Example
A NIFTY 25,000 call trades at a premium of ₹150. Buying one lot costs 150 × 75 = ₹11,250, and every ₹1 move in the premium changes your P&L by ₹75. In BANKNIFTY, a ₹300 premium costs 300 × 35 = ₹10,500 per lot with ₹35 per point of premium movement. For futures, one NIFTY lot at 25,000 controls notional exposure of 25,000 × 75 = ₹18,75,000 — which is what margin requirements and risk are really scaled against. Hypothetical prices.
Why it matters
Lot size makes F&O position sizing chunky: your size can only step in whole lots, and if one lot risks more than your per-trade risk budget allows, the correct trade is none at all. Lot size revisions also silently change a running strategy’s risk — the same “2 lots” rule means different rupee exposure after a revision — so systematic traders parameterize strategies in rupee risk, not lot counts.
In INDfolio AI, backtests use the correct contract specifications so results reflect real lot-based sizing — see Options.