How position size is calculated
Position sizing sets how many units you can hold so that, if the price reaches the stop, the loss stays within a fixed share of the portfolio.
A wider stop means fewer units, and vice versa. The calculator illustrates the arithmetic only; it does not suggest a risk level or entry price.
Formula
- Amount at risk = Portfolio size × Risk %
- Units = Amount at risk ÷ (Entry − Stop), rounded down
- Position value = Units × Entry
Assumptions
- Long positions only; the stop is below the entry.
- The stop fills at its price; a gap down at the open can fill lower.
- Rounded down to whole units; exchange lot sizes are ignored.
- Trading fees and taxes are ignored.