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📦 What Is Lot Size? Complete Guide With Latest Lot Sizes (2025 Onetrader Edition)
(Onetrader Derivatives Masterclass — For Beginners & Traders)
If you want to trade Futures & Options (F&O), there is one number you must understand before placing any trade:
👉 LOT SIZE
Most new traders don’t know what it means… and end up taking wrong exposure, wrong stop-loss size, and wrong capital allocation.
Let’s fix that.
Here is the latest, corrected, simplified article — Onetrader quality 🔥
Also Read: How to Analyze a Company’s Quarterly Results (Step-by-Step Guide )
🧠 What Is Lot Size?
Lot Size = the fixed quantity you must trade in Futures & Options.
Unlike equity where you can buy 1 share,
F&O can only be traded in multiples of the exchange-defined lot size.
Example:
If Nifty lot size = 75
You must trade either:
- 1 lot = 75 quantity
- 2 lots = 150 quantity
- 3 lots = 225 quantity
You can’t trade 1 unit or 20 units.
🔥 Why Does Lot Size Exist?
SEBI and NSE create lot sizes because:
✔️ To maintain liquidity
✔️ To control contract value
✔️ To protect traders from huge volatility
✔️ To create uniformity across the market
If index prices go too high, lot size is reduced.
If prices fall too low, lot size is increased.
📊 Latest Lot Sizes (Correct & Updated – 2025)
Index Lot Sizes (NSE F&O)
| Index | Latest Lot Size (2025) |
|---|---|
| NIFTY 50 | 75 units |
| BANKNIFTY | 35 units |
| FINNIFTY | 65 units |
| MIDCPNIFTY | 140 units |
| NIFTY NEXT 50 | 25 units |
Note: Exchanges may revise lot sizes when contract values move too high or low. These are current active lot sizes being traded now.
🧮 How Lot Size Affects Contract Value
Formula:
Contract Value = Lot Size × Price
Example:
If NIFTY = 24,000
Lot Size = 75
👉 Contract Value = 24,000 × 75
👉 ₹18,00,000 exposure
You don’t pay 18 lakhs…
You only pay the margin, usually 10–20%.
But your risk is still based on the full contract value.
⚠️ How Lot Size Affects Your Risk
Example:
Nifty moves 10 points.
Loss/Profit = 10 points × 75 = ₹750 per lot.
If you trade 2 lots,
= ₹1,500 movement.
This is why lot size determines:
✔️ Your stop-loss amount
✔️ Your risk-per-trade
✔️ Your capital requirement
✔️ Your reward potential
📌 Stock Lot Sizes (Important Note)
Stock F&O lot sizes differ for each stock.
Examples (2025 common sizes):
| Stock | Lot Size |
|---|---|
| RELIANCE | 250 |
| TCS | 150 |
| INFY | 300 |
| HDFC BANK | 550 |
| ICICI BANK | 700 |
(Note: These are examples. Stock lot sizes keep changing depending on price movement.)
Always check the latest list before trading.
🧱 Why Lot Size Keeps Changing
NSE wants contract value to stay around ₹5–12 lakhs per lot.
So if index price rises too much → they reduce lot size
If index price falls too much → they increase lot size
This is for trader safety.
🎯 Onetrader Rule (Very Important)
“Never trade F&O without checking lot size.
Your profit and STOP-LOSS depend on it.”
Knowing lot size = knowing your risk.
🧠 Quick Checklist Before Placing Any F&O Trade
✔️ Check lot size
✔️ Calculate contract value
✔️ Calculate risk per point
✔️ Check margin requirement
✔️ Place stop-loss based on lot size
✔️ Avoid overexposure
🏁 Final Onetrader Conclusion
Lot size looks like a simple number…
but it decides everything in your trade:
- Capital
- Leverage
- Risk
- Reward
- Position size
- Exposure
Once you understand lot size properly,
you’ll never take oversized trades or blow up your capital again.
This is the first step to becoming a professional-level F&O trader.
❓ FAQ Section
1️⃣ What is lot size in F&O?
Lot size is the fixed number of units you must trade in a futures or options contract.
2️⃣ Why does NSE change lot size?
To keep contract value stable as price moves up or down.
3️⃣ What is the current Nifty lot size?
75 units (2025).
4️⃣ What is the current Bank Nifty lot size?
35 units.
5️⃣ Do stock lot sizes also change?
Yes — they are reviewed regularly based on price movement.