Interactive toolRuns in your browser

Position Size Calculator

Turn a fixed-fractional risk rule into a concrete number of lots, so a stopped-out trade costs only a small, survivable slice of your capital.

Quick answer: The position size calculator is the single most important risk-management tool: it decides how much to trade so that being wrong is affordable. It takes your capital and the percentage you are willing to lose on the trade, works out the rupee risk budget, then divides that budget by the per-lot loss at your stop (stop distance in points multiplied by the point value of one lot). The result is the largest whole number of lots whose worst-case loss stays inside the budget, which is what keeps a losing streak from ending your account.

Trading capital (₹)Risk per trade (%)

Entry priceStop pricePoint value per lot (₹)

How to use it

Enter your capital, the percent you will risk, and the entry and stop prices. Point value per lot is the rupee change in one lot for a one-point move in price (75 for a standard Nifty lot; Bank Nifty and stock futures use their own lot sizes). The output shows the rupee risk budget, the loss per lot at your stop, the whole number of lots that fits, and the actual rupee at risk. It ignores brokerage, STT and slippage, which make the real loss slightly larger, so size a little inside the limit rather than at it.

Formula

Lots = floor( (Capital × Risk% ÷ 100) ÷ ( |Entry − Stop| × Point value per lot ) )

The numerator is the rupee risk budget (the most you accept losing on this one trade); the denominator is the loss on one lot if the stop is hit. floor() rounds down so the budget is never exceeded. Sizing off the stop distance — not the notional value or the margin — is what makes risk constant across trades.

Frequently asked questions

Why is position sizing the core of risk management?

Edge decides whether you win over hundreds of trades; position size decides whether you survive to get there. Sizing every trade to lose only a small fixed fraction of capital caps the damage of any single loss and of an unlucky losing streak, which is the whole point of capital preservation.

Why does it round down to whole lots?

Exchange-traded futures and options in India trade in fixed lot sizes, so you cannot buy a fraction of a lot. Rounding down keeps the worst-case loss inside your risk budget rather than nudging it over.

What is point value per lot?

It is the rupee value of a one-point move in the instrument for a single lot. For a Nifty contract with a lot size of 75, one index point is worth 75 rupees per lot, so you enter 75. Bank Nifty and single-stock contracts have different lot sizes, so use the current contract specification.

It says zero lots. What does that mean?

Your risk budget is smaller than the loss on a single lot at that stop distance. That is the tool protecting you: either widen the stop, raise the risk percentage, or accept that this trade does not fit your capital and skip it. Forcing the position on would break your risk rule.

Does it include brokerage and taxes?

No. The figure is the raw price risk. Brokerage, STT, exchange fees and slippage add to the real loss, so treat the output as a floor, not the exact amount, and leave a small buffer.

What risk percentage is sensible?

Many traders cap single-trade risk at 0.5 to 2 percent of capital as a rule of thumb, because it keeps any one loss small relative to the account. This is a heuristic, not a rule of nature; the tool sizes the position for whatever percentage you enter and does not recommend a number.

Runs entirely in your browser — no data leaves your device. Illustrative and educational only; real-world charges and market conditions apply in practice.