Derivatives
Lot size
Lot size is the fixed number of units in one derivatives contract; futures and options can be traded only in whole multiples of it.
In the cash market you can buy one share. In futures and options you cannot. The exchange fixes a lot size for each contract, and every order is for one lot or a whole multiple of it. The lot size is the number of units one contract covers: shares for a stock future or option, index units for Nifty or Bank Nifty.
Lot size turns points into rupees. Profit or loss per lot equals points moved times lot size. The same multiplication gives contract value: price times lot size. This is why a 10-point move means very different money in different contracts, and why a stock option can tie up more rupee risk than its small premium suggests.
Exchanges revise lot sizes. NSE reviews them periodically to keep contract values within a band, so a number you read in a blog or an old video may be out of date. We do not state current lot sizes on this site. Check the current NSE circular, or the contract details in your broker's order window.
The common mistake is sizing in lots before working out rupees. A trader says one lot is small, without multiplying the stop-loss distance by the lot size. If that number is more than you planned to lose on one trade, the position is too big even at one lot. The right action is to pick a smaller contract or skip the trade.
Worked example
Points to rupees, worked backwards
Illustrative numbers. A Nifty futures trade has its entry at 25,000 and its stop-loss at 24,940, a risk of 60 points per unit. Risk per lot is 60 times the lot size. With a ₹5,000 limit per trade, one lot fits only if the lot size is 83 units or fewer, because 5,000 divided by 60 is about 83. Take the real lot size from the current NSE circular and multiply. If the answer is above ₹5,000, even one lot is too big for your limit.
In WizeBuySell
The WizeBuySell option strategies name the contract, for example “Buy PE 23050 (Same Week)” on Nifty Options Buying, but not how many lots to trade. The indicators do not know the lot size or your capital, and they do not place orders. Converting the stop-loss distance into rupees per lot, and deciding the number of lots, is your job. Take the lot size from the current NSE circular.