NubraNubra Position Size Calculator
Risk-based share quantity for a planned stock or F&O trade
What is it
What is a position size calculator?
A position size calculator tells you how many shares to buy so that a single loss, if your stoploss is hit, stays within a fixed percentage of your capital. It turns three inputs, your available funds, the percentage you are willing to risk, and the distance from entry to stoploss, into one output: the exact quantity to buy.
Position sizing is one of the few parts of a trade you fully control before you place an order. The stock may move in your favour or against you, but the size of the position, and therefore the maximum rupee loss on that single trade, is fixed the moment you enter it.
Example
Example: Rs.5,00,000 capital, 1% risk
Say you have Rs.5,00,000 in trading capital and want to risk 1% (Rs.5,000) on a trade. You plan to buy at Rs.1,000 with a stop-loss at Rs.950, a risk of Rs.50 per share.
| Input | Value |
|---|---|
| Funds available | Rs.5,00,000 |
| Risk boundary | 1% (Rs.5,000) |
| Buy price | Rs.1,000 |
| Stoploss | Rs.950 |
| Risk per share | Rs.50 |
| Position size | 100 shares |
Rs.5,000 divided by Rs.50 risk per share gives 100 shares: an investment of Rs.1,00,000, or 20% of the capital available.
Formula
How position size is calculated
The calculator works out the risk amount from your funds and risk boundary, then divides it by the risk per share to get the position size.
Potential risk (Rs.) = Funds available x (Risk boundary % / 100)The maximum rupee amount you are willing to lose if the stop-loss is hit.
Risk per share (Rs.) = Buy price - StoplossThe rupee loss on one share between entry and the stoploss price.
Shares to buy = Potential risk / Risk per shareRounded down to a whole number of shares, since you cannot trade a fraction of a share.
How to use it
3 steps to use this calculator
- Set your funds and risk boundaryEnter available trading funds and the percentage you are willing to risk on one trade.
- Enter your buy price and stoplossAdd the planned entry and the price at which you will exit if the trade goes against you. The stoploss must be below buy price.
- Read off your position sizeThe result shows shares to buy, investment required and potential risk in rupees.
Reading the result
The numbers that matter
Why it helps
What this calculator gives you
- Keep every trade's risk consistentDifferent stock prices can carry the same rupee risk once position size adjusts for the stop-loss distance.
- Remove the guesswork from quantityDerive quantity from the risk you decided to take instead of picking a round number of shares.
- Catch oversized trades before you place themCapital-utilisation checks flag trades that would need more capital than you have.
FAQ
Frequently asked questions
What is a position size calculator?
A position size calculator works out how many shares to buy from your available funds, risk percentage, buy price and stoploss. It sizes the quantity so a stop-loss hit stays within your chosen risk boundary.
How is position size different from lot size or quantity?
Lot size is an exchange-set trading bundle. Position size is the quantity calculated from the money you are willing to risk and your stop-loss distance.
What risk percentage should I use per trade?
Many traders use a small fixed risk percentage such as 0.5% to 2% of capital per trade. The appropriate limit depends on your strategy, diversification and total exposure.
Why does the calculator show a warning about my stop-loss?
A long position needs a stop-loss below its buy price. Otherwise the risk per share is zero or negative and the calculator cannot produce a meaningful risk-controlled quantity.
What if the investment amount is more than my available capital?
The calculator flags this when the number of shares required by the risk budget costs more than your capital. You can reduce the risk boundary, widen the stop-loss distance, or add funds.
Does this calculator include brokerage, margin or taxes?
No. It calculates quantity only from capital, risk boundary, entry price and stop-loss. Brokerage, margin, taxes and other charges are not included.
Can I use this for intraday and swing or positional trades?
Yes. The sizing formula is the same. Intraday stops are usually tighter, while swing or positional stops can be wider, which affects the resulting quantity.
This calculator computes share quantity from the funds, risk boundary and prices you enter. It does not include brokerage, margin, taxes or other charges, and it is not investment advice. Always confirm the stoploss sits below your buy price and the resulting investment amount is within your available funds.