Risk Per Trade Calculator
Check the exact rupee and percentage of capital a planned trade puts at risk if the stop-loss is hit.
Quick answer: The risk per trade calculator measures the downside of a position you have already sized. It multiplies the distance from entry to stop by the quantity to get the rupee loss if the stop triggers, then expresses that as a percentage of your capital. A gentle warning appears when the figure crosses two percent, a common rule-of-thumb ceiling for a single trade.
How to use it
Enter capital, the total quantity you will hold (lots multiplied by lot size), and the entry and stop prices. The output is the rupee loss at the stop and that loss as a percentage of capital. Quantity is in units, so a one-lot Nifty position is 65 units. The calculation excludes charges, which make the real loss slightly larger.
Formula
Rupee risk = |Entry − Stop| × Quantity ; Risk% = Rupee risk ÷ Capital × 100
Quantity is total units held. For lot-based instruments, Quantity = number of lots × lot size.
Limitations of the Risk Per Trade Calculator
The Risk Per Trade Calculator is a teaching aid, not a live risk system. It does not model the following:
- Trading costs (brokerage, STT, exchange fees, slippage), which add to the loss beyond the price move
- Overnight and event gaps that jump through the stop, realising more than the budgeted loss
- Aggregate risk across several correlated positions held at the same time
- Any assumption that the stop always fills exactly at its stated level
Frequently asked questions
How is this different from the position size tool?
The position size tool starts from a target risk and gives you a quantity. This tool does the reverse: you supply the quantity and it reports the resulting risk, useful for auditing what per-trade risk a backtest's fixed quantity actually implied.
Why is the per-trade fraction the key input to a backtested risk of ruin?
Because risk of ruin rises sharply as the per-trade fraction increases: losses compound, so risking 10 percent lets a few backtested losses in a row halve the account, while at 1 percent the same run is minor. Mapping the fraction against the backtest's worst streak is the point of measuring it.
Should quantity be in lots or units?
Units. Multiply lots by the lot size first. One Nifty lot is 65 units, so three lots is 195 units — the same convention your backtest's trade log should record.
Can a backtested gap exceed the risk-per-trade figure?
Yes. An overnight or event gap can jump straight through the stop, realising a loss larger than the budgeted percentage. A backtest that assumes the stop always fills at its level understates the true worst case, so gap fills must be modelled.
Does controlling per-trade risk in a backtest control total risk?
Not by itself. If the backtest holds several correlated positions, their combined loss on one adverse move can be a multiple of the per-trade figure, so an honest backtest must also cap and measure aggregate open risk (heat), not just the single-trade number.
Runs entirely in your browser — no data leaves your device. Illustrative and educational only; real-world charges and market conditions apply in practice.