Calculator
Position size calculator
Size the trade from the stop, not from the conviction — how many units a given risk budget actually buys.
100 units
100 shares · ₹2,45,000 position value
- Risk budget₹5,000
- Loss if stopped out₹5,000
- Stop distance2.04% (₹50)
- Capital needed₹2,45,000
- Reward : risk3 : 1
Hover a segment for value + share.
Size = risk budget ÷ loss per share, rounded down to whole lots. Gap risk and slippage sit on top of the stop.
What this calculator answers
With a ₹5,00,000 account risking 1% (₹5,000), an entry at 2,450 and a stop at 2,400 the risk per unit is ₹50, so the position is 100 units — a ₹2.45 lakh position that loses exactly the risk budget if the stop fills. Round down to whole lots and the size only ever gets smaller.
How it is calculated
Risk budget = account × risk %. Units = risk budget ÷ (entry − stop), floored to a whole number of lots. Capital required is position value × the margin block, and reward:risk is (target − entry) ÷ (entry − stop).
The stop is assumed to fill at the price you set. Gaps, slippage and brokerage sit on top, so the realised loss on a stop can exceed the budget. At 100% margin the capital required is the full position value; a lower margin block is what leverage would free up.
Common questions
What risk per trade is sane?
Most risk frameworks land between 0.5% and 2% of the account per trade, because a run of losses is normal. At 1% you can absorb ten consecutive losses and still have 90% of the account — at 10% you cannot.
Why does position size come from the stop, not the target?
The stop is the only number that caps the loss. Sizing from the target just picks an amount and then works backwards to invent a risk figure, which is how accounts get sized past what they can survive.
What if the stop is below zero on the slider?
Then the calculator returns zero units rather than a negative size, and says so. A stop above entry is a mislabelled trade.
Source & freshness
- Source
- Deterministic formula in lib/calculators.ts
- Timeliness
- Static-verified
- Method
- calculated
- Note
- Illustrative projection from your inputs — not a market quote.