Position size calculator for traders: how many shares or lots to buy
Position sizing decides how much you can lose if a trade fails. This calculator turns your capital, risk percentage, entry and stop into a quantity.
How to use this calculator
- Enter your trading capital.
- Enter the percentage of capital you are willing to lose on one trade.
- Enter your entry price and your stop-loss price.
- For futures and options enter the lot size. Read the quantity, lots, position value and share of capital.
Worked examples
Example 1
₹5,00,000 capital, 1% risk, buying at ₹250 with a stop at ₹240.
You enter
| Trading capital | ₹5,00,000 |
|---|---|
| Risk per trade (% of capital) | 1% |
| Entry price | ₹250 |
| Stop-loss price | ₹240 |
| Lot size (optional, for futures and options) | 1 |
You get
| Amount you risk | ₹5,000 |
|---|---|
| Risk per share | ₹10.00 |
| Quantity | 500 |
| Position value | ₹1,25,000 |
| Position as a share of capital | 25% |
Example 2
A futures contract with a lot of 25, entry 1,800, stop 1,770, risking 1% of ₹10,00,000.
You enter
| Trading capital | ₹10,00,000 |
|---|---|
| Risk per trade (% of capital) | 1% |
| Entry price | ₹1,800 |
| Stop-loss price | ₹1,770 |
| Lot size (optional, for futures and options) | 25 |
You get
| Amount you risk | ₹10,000 |
|---|---|
| Risk per share | ₹30.00 |
| Quantity | 325 |
| Lots | 13 |
| Position value | ₹5,85,000 |
| Position as a share of capital | 58.5% |
How it works
If you risk 1% of ₹5,00,000, you accept a ₹5,000 loss if the stop is hit. The distance between entry and stop sets how many shares that allows: a wider stop means fewer shares.
Real exits can be worse than the stop because of gaps, slippage and costs. Treat the risk amount as a target, not a guarantee.
Formula
Quantity = (capital x risk %) / |entry - stop|, rounded down to whole lots.
Common questions
What risk percentage is sensible?
Many people use between 0.5% and 2%; this is education, not advice.
Does it include brokerage?
No.
What if the position is bigger than my capital?
The tool warns you; use a wider stop or fewer shares.
Calculators give estimates for learning and planning. They are not financial, tax, legal or medical advice, and results depend entirely on the numbers you enter. Check rates, limits and rules with an official source or a qualified professional before acting.