Where a stop loss belongs
A stop loss is not a wish about how much you would like to lose. It is a statement about price: “if the market trades here, the reason I opened this position no longer exists.” Those are completely different things, and confusing them is the most common structural mistake in retail trading.
Invalidation, not affordability
Ask the question in this order:
- Where is my idea wrong? That price is the stop level. It comes from the chart — beyond the swing that defines the move, past the level that was supposed to hold, outside the range you expected to contain price.
- How far is that from entry? That distance is an input, not a choice.
- What size keeps the loss inside my risk budget? That is the arithmetic from Lesson 1.
Do it in the reverse order — “I can afford $50, so my stop goes 10 points away” — and you have placed the stop somewhere the market has no reason to respect. It will be hit by ordinary noise, and you will conclude the method does not work when in fact the exit was never connected to it.
Give it room for noise
Every instrument breathes. A stop must sit outside that normal breathing, or randomness alone will take you out. A practical way to measure the breath is average range: if a market typically travels 40 points in a session, a 10-point stop is inside the noise band, no matter how good the entry looked.
This is also why the same idea has different sizes on different instruments. Gold and a major currency pair breathe at completely different amplitudes. Copying someone else's lot size across instruments makes no sense at all.
Just below the obvious level is the worst place
Clusters of stops sit exactly where everyone can see them: a few points under the recent low, right above the round number. Those clusters are liquidity, and price frequently reaches into them before continuing in the original direction.
The practical adjustment is not to abandon the level but to sit further from the crowd, and to accept the smaller position size that follows. A stop that survives the sweep and a smaller size beats a tight stop that gets collected on the way up.
Things that quietly widen your real risk
- Gaps. A stop is an instruction to exit at the best available price once a level trades, not a guarantee of that price. Over a weekend or a data release, the fill can be far worse. Position size, not the stop, is your protection here.
- Spread widening. Around news, the spread can expand and reach your stop while the mid price never did. Placing stops immediately behind the level, rather than on it, helps.
- Slippage on exit. In fast markets the exit is worse than the level. Assume a real loss slightly larger than your calculation, and do not size as if the stop were exact.
Moving a stop: the one legitimate direction
Moving a stop in your favour — reducing the risk once price has moved your way — is management. Moving it away to avoid being stopped out is not management; it is cancelling the plan while pretending to have one. If you find yourself doing it, that is a signal about size: the position was too large to be held with the stop where it belonged.
Breakeven stops are not free
Sliding the stop to entry as soon as a trade moves a little feels prudent, and it does remove the loss. It also converts many eventual winners into scratches, because most trades pull back through the entry before working. If you use it, apply it after a defined threshold — a measured multiple of the initial risk — rather than emotionally, and know that the win rate will fall in exchange for the comfort.
The test
Before entering, answer this in one sentence: “I am wrong if price trades at X, because Y.” If you cannot fill in Y with something about the market — rather than something about your account — the trade has no defined exit yet, and the position should not exist.
Next: Leverage, margin and the number that actually kills accounts →