Place it where the idea is wrong, not where the pain starts
The most common mistake is picking a stop distance based on how much money you are willing to lose. That number has nothing to do with the market. The stop belongs at the price that proves your reason for the trade was wrong — below the structure you bought from, above the level you sold from.
Once the stop is at a technically sound level, the position size is what you adjust to control the money at risk. That order of operations is the whole discipline.
Volatility-based stops
A fixed 2% stop is too tight on Bitcoin and absurdly wide on EUR/USD. Using a volatility measure such as Average True Range gives a stop that adapts: roughly 1.5 to 2 ATR beyond your entry structure keeps the stop outside normal noise on either instrument.
Trailing stops
A trailing stop follows price at a fixed distance and never moves backwards, converting an open profit into a locked-in floor. It is well suited to trends and poorly suited to ranges, where the constant chop will stop you out repeatedly at the same distance.
The limits of a stop
- Gaps and weekend moves can skip your level entirely — a stop is not a guarantee.
- Guaranteed stop-loss orders remove that risk but charge a premium.
- Widening a stop mid-trade because price is approaching it converts a planned small loss into an unplanned large one.
Account $10,000, risking 1% = $100. Entry $50, technical stop $47 → risk per unit $3 → position size 33 units. The money at risk stayed fixed while the stop stayed where the chart said it belonged.