Lot size is the standardized quantity of the underlying asset represented by one derivatives contract. In futures and options trading, you cannot buy fractional contracts—you must trade in whole lots. Lot sizes are set by exchanges to maintain appropriate contract values and ensure liquidity. They determine your minimum position size and affect margin requirements.
- Fixed number of units per contract
- Must trade in whole lots (no fractions)
- Determines minimum position size and margin
How Lot Size Works
Lot size determines contract value:
Lot Size Calculation:
Nifty Futures:
- Index Value: 22,000
- Lot Size: 50
- Contract Value: 22,000 × 50 = ₹11,00,000
Bank Nifty Futures:
- Index Value: 47,000
- Lot Size: 15
- Contract Value: 47,000 × 15 = ₹7,05,000
Stock Futures (Reliance):
- Stock Price: ₹2,500
- Lot Size: 250
- Contract Value: 2,500 × 250 = ₹6,25,000
Margin (assume 10%):
Nifty: ₹1,10,000
Bank Nifty: ₹70,500
Reliance: ₹62,500
Quick Reference: Common Lot Sizes
| Contract | Lot Size | Approx Value |
|---|---|---|
| Nifty 50 | 50 | ₹11,00,000 |
| Bank Nifty | 15 | ₹7,00,000 |
| Fin Nifty | 40 | ₹8,00,000 |
| Stock F&O | Varies | ₹5-10 lakhs |
Values approximate and change with price
Example: Position Sizing with Lots
Trading Nifty Options:
| Factor | Value |
|---|---|
| Nifty | 22,000 |
| Lot Size | 50 |
| ATM Call Premium | ₹200 |
| Cost per Lot | ₹200 × 50 = ₹10,000 |
| Want to risk ₹25,000 | |
| Position | 2.5 lots → 2 lots (round down) |
| Actual Risk | ₹20,000 |
Lot size is the fixed number of units in one derivatives contract. Nifty lot size is 50; Bank Nifty is 15. Contract value equals price times lot size. You must trade whole lots—no fractions. Lot sizes determine minimum position size and margin requirements.
Lot Size Impact
On Position Sizing
Minimum position = 1 lot. May be too large for small accounts.
On Margin Requirements
Margin = Contract Value × Margin %. Larger lots need more margin.
On Profit/Loss
P/L = Price Change × Lot Size. Each point = Lot Size rupees.
On Liquidity
Standardized lots ensure fungibility and liquidity.
Lot Size Changes
Exchanges revise lot sizes based on:
- Price movements (higher price = smaller lot)
- Contract value targets (maintain accessible values)
- Market conditions and liquidity
Check exchange circulars for current lot sizes.
Calculating P/L with Lot Size
Nifty Futures P/L:
Entry: 22,000
Exit: 22,150
Move: +150 points
Lot Size: 50
P/L = 150 × 50 = ₹7,500 per lot
If traded 3 lots:
P/L = ₹7,500 × 3 = ₹22,500
Common Mistakes
-
Not checking lot size – Different stocks have different lot sizes.
-
Oversizing positions – One lot may be too much for your account.
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Forgetting lot size in P/L – Each point move = lot size in rupees.
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Missing lot size changes – Exchanges revise periodically.
How JournalPlus Tracks Lot Size
JournalPlus automatically applies correct lot sizes for contract value calculations, helping you track true P/L and position sizing across different instruments.
