Why your stop width must decide your size
If the stop is placed from structure, size is a division problem — not a preference.
Many traders reverse the order. They decide they want fifty shares, then stretch the stop until the pound risk feels tolerable. That habit turns technical invalidation into decoration.
Structure first
On a daily chart, invalidation is often the swing that would break the pattern you claimed to trade. Measure from planned entry to that level. That distance is fixed by the market; your comfort is not a reason to move it.
Then divide
Take the pounds you are willing to lose on the idea — commonly half a percent to one percent of account equity — and divide by the pounds you lose per share (or per contract) if the stop is hit. Round down. That integer is the size.
What changes when volatility expands
If ATR widens, the same structural stop may sit further away. Size shrinks automatically when you keep the risk budget fixed. Traders who keep share count constant while stops widen are quietly raising risk.
Practise the sequence in our method overview or bring three trades to the intensive.