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Glossary

What Is a Trading Lot Size?

A lot size is the fixed number of units in one futures or options contract. You can only trade F&O in whole lots, so the lot size sets the smallest position you can take.

QuantPower Research · Updated 3 Nov 2026 · 2 min read

Current index lot sizes

ContractLot size from the January 2026 series
Nifty 5065
Nifty Bank30
Nifty Financial Services (FinNifty)60

Nifty's lot was 75 before the January 2026 series. Check the exchange's contract specifications before each new series, because lot sizes are revised periodically.

How lot sizes are set

Exchanges set lot sizes so that each contract has at least a minimum value. Under SEBI's measures from November 2024, a new index derivative contract must be worth at least ₹15 lakh when introduced. Exchanges review lot sizes regularly and revise them when price changes move contract values too far from the target.

An example

Example
You buy 2 lots of the Nifty 25,000 call at ₹280.50. The quantity is 2 × 65 = 130 units, and the premium is 130 × 280.50 = ₹36,465. A one-point move in the option changes your P&L by ₹130.
Formula
Position value = number of lots × lot size × price. Contract value of one lot of futures = lot size × futures price.

For Nifty futures at 25,000, one lot has a contract value of 65 × 25,000 = ₹16,25,000.

Why lot size matters

  • Risk per point: every point in Nifty moves one lot of futures by ₹65.
  • Margin: margin is a share of the contract value, so a larger lot needs more margin.
  • Strategy settings: algorithms and backtests that use quantities in units must be updated when lot sizes change. Settings in lots adjust automatically.
  • Order rejections: an order that is not a whole number of lots is rejected.

Learn more

Frequently asked questions

What is the Nifty lot size?

65 units from the January 2026 series.

Can I trade less than one lot?

Not in F&O. The smallest order is one lot.

Do lot sizes change for open positions?

Revisions apply to new contracts. Existing contracts usually keep their lot size until they expire. Check the exchange circular for each revision.

Trading involves substantial risk. Examples on this page are hypothetical and are not investment advice.