Enter your capital, the percentage you are willing to risk, your entry and your stop-loss. This position size calculator shows how many shares to buy so that a stopped-out trade costs only what you planned.
Position Size Calculator
Start from the loss you can accept, and work out the quantity from there.
Quantity = risk amount ÷ (entry − stop-loss), rounded down, and never more than your capital allows. The loss shown is before brokerage and charges.
Your trade in detail
| Item | Value |
|---|
Most traders decide how many shares to buy by how much they can afford, not by how much they can afford to lose. A position size calculator flips that around: you choose the loss first, usually 1% of your capital, and the quantity falls out of that. Stock Charcha built it to start from risk every time.
How do you use this position size calculator in 3 steps?
- Enter your trading capital and the percentage of it you are willing to risk on one trade.
- Enter your entry price and your stop-loss price.
- Add a target price if you have one, then read the quantity, the position value and the amount at risk.
A wider stop-loss simply means a smaller quantity, not a bigger loss.
How does the position size calculator work out the quantity?
It compares two limits and uses whichever is smaller: what your risk budget allows, and what your capital and leverage can actually buy.
Quantity by risk = Risk amount ÷ (Entry price − Stop-loss price)
Quantity by capital = Capital × Leverage ÷ Entry price
Risk amount is your capital times your chosen risk percentage. The quantity is rounded down, because you cannot buy a fraction of a share.
What does a worked example look like?
Take ₹2,00,000 capital, 1% risk, an entry of ₹500 and a stop-loss of ₹490, with a target of ₹530. These figures are illustrative.
| Item | Value |
|---|---|
| Risk amount (1% of capital) | ₹2,000 |
| Risk per share | ₹10 |
| Quantity by risk | 200 shares |
| Quantity by capital | 400 shares |
| Quantity to trade | 200 shares |
| Position value | ₹1,00,000 |
| Risk-reward ratio | 1 : 3.00 |
Risk is the binding limit here, so 200 shares is the answer, even though capital could stretch to 400. A hit stop-loss costs exactly the ₹2,000 you planned, before charges.
How does the stop-loss distance change your quantity?
A tighter stop-loss lets you buy more shares for the same risk, because each share risks less. Here is the same ₹2,00,000 capital and 1% risk, with different stop-loss distances from a ₹500 entry.
| Stop-loss distance | Stop-loss price | Quantity by risk | Quantity by capital | Quantity to trade | Amount at risk |
|---|---|---|---|---|---|
| 0.5% (₹497.50) | 800 | 400 | 400 | ₹1,000 | |
| 1% (₹495.00) | 400 | 400 | 400 | ₹2,000 | |
| 2% (₹490.00) | 200 | 400 | 200 | ₹2,000 | |
| 5% (₹475.00) | 80 | 400 | 80 | ₹2,000 |
At a 0.5% stop, capital becomes the limit before risk does, so the amount at risk falls below your 1% budget. Stock Charcha’s position size calculator always picks the smaller of the two quantities.
Why does risking a fixed percentage matter over many trades?
A string of losses hurts less when each one is small and consistent. Here is what ₹1,00,000 becomes after a run of losses, at two different risk levels.
| Losing streak | At 1% risk per trade | At 2% risk per trade |
|---|---|---|
| 5 losses in a row | 95.1% left (5.2% to recover) | 90.4% left (10.6% to recover) |
| 10 losses in a row | 90.4% left (10.6% to recover) | 81.7% left (22.4% to recover) |
| 20 losses in a row | 81.8% left (22.3% to recover) | 66.8% left (49.8% to recover) |
Capital lost to a losing streak needs a larger percentage gain to recover, because the base has shrunk. Position sizing will not stop a losing streak, but it keeps one from ending your trading.
What is risk-reward, and how does it change the win rate you need?
Risk-reward compares what you stand to lose with what you stand to gain. A ratio of 1 : 3, as in the example above, means the target is three times as far as the stop-loss.
| Risk-reward ratio | Win rate needed to break even |
|---|---|
| 1 : 1 | 50.0% |
| 1 : 2 | 33.3% |
| 1 : 3 | 25.0% |
At 1 : 3 you only need to be right one time in four, before charges, to break even. A tight ratio demands a much higher win rate to survive.
What does this position size calculator leave out?
It does not include brokerage, STT or other charges, so the real break-even win rate is slightly higher. Our brokerage calculator adds those up. It also assumes your stop-loss is actually hit at that price, which a sharp gap can break.
For margin and leverage on an intraday trade, see our intraday margin calculator. This is an educational tool, not a trading system or a recommendation. Investments in the securities market are subject to market risks.
Where should you go after using the position size calculator?
Check the margin and exposure for the same trade with the intraday margin calculator, and the net profit after charges and tax with the stock profit and loss calculator. Read the top investing mistakes to avoid.
The Trading section of the Charcha Knowledge Hub has more. Run the position size calculator before every trade, so your risk is a number you chose, not discovered afterwards.
Related calculators
- Intraday margin calculator
- Stock profit and loss calculator
- Brokerage calculator
- Stock average calculator
Last updated: 3 October 2026. This page uses no rates, slabs or charges, so the maths stays the same until the method changes.
Founder of Stock Charcha. Stock market enthusiast, actively investing since November 2022. About the author
Educational content only. This page is not personalised financial advice, and nothing here is a recommendation to buy or sell any stock. Please do your own research or speak to a SEBI-registered adviser, and read our disclaimer.
Frequently asked questions
How much of my capital should I risk on one trade?
Many traders use 0.5% to 1% of capital per trade, so a losing streak does not do lasting damage. Risking more than 2% to 3% on one trade is considered aggressive by most risk frameworks. Choose a number you can sustain through several losses in a row.
Does a wider stop-loss mean a bigger loss?
Not if your position size calculator adjusts the quantity. A wider stop-loss means fewer shares for the same risk amount, so the rupee loss can stay the same even though the stop is further away in price.
What is a good risk-reward ratio?
Many traders aim for at least 1 : 2, so the target is twice as far as the stop-loss. A better ratio needs a lower win rate to break even, which gives you more room for losing trades without losing money overall.
Does the position size calculator guarantee I will not lose more than planned?
No. It sizes the position assuming your stop-loss is filled at that exact price. A gap, a halt or fast market conditions can fill your stop-loss worse than planned, so the real loss can exceed the calculated amount.
Should I use the same risk percentage for every trade?
Many traders do, for consistency, though some reduce it after a few losses in a row or for setups they trust less. Whatever rule you choose, keeping it consistent is usually more useful than changing it trade by trade.