How to choose a stop-loss level

2026-11-01

A stop-loss marks the price at which your reason for being in the trade no longer holds. It is a statement about the setup, not about your account — and the most common mistake is deriving it from the second thing instead of the first.

Get the order wrong and everything downstream is wrong with it.

The two ways people choose a stop

From the account. “I am willing to lose $200, so with this position size the stop goes at 98.” The level is wherever the budget lands. It has no relationship to the chart, and price reaching it tells you nothing except that you have spent your allowance.

From the setup. “This is a long because the level at 96 held. If it trades back through 96, that reason is gone.” The stop goes at 96, and reaching it is genuinely informative — the thing you were relying on stopped being true.

The second is the only one that produces a stop worth having. The first produces a budget with a price attached.

Why the order matters

Once the stop comes from the setup, everything else follows without further decisions:

Stop — where the idea is invalidated. From the chart.
Risk budget — a percentage of the account, decided in advance and not per-trade.
Position size — determined by 1 and 2, via the position size calculator.
Leverage — position size ÷ balance. An output; you did not choose it.
Sanity check — does liquidation arrive before the stop? The leverage and stop-loss table answers this. If it does, the position is too large.

Running this backwards — picking a size, then fitting a stop to it — breaks the chain at the first link. The stop is now arbitrary, the R multiple computed from it is meaningless, and the statistics you build on those R multiples describe nothing.

Where invalidation usually lives

The specific level depends entirely on why you are in the trade. Some common shapes:

Structure. The swing low that made this a higher low. Through it, the structure you were trading is gone.
A level. The support that held. Through it, it did not hold.
Volatility. A multiple of recent range, for setups where the thesis is about direction rather than a specific level. This adapts the distance to conditions rather than to your balance, which is the right property.
Time. Less common and often underrated: if the move has not happened within a defined window, the reason has expired even if price has not moved.

What these share is that they are defined by the market. None of them consult your account size.

Placing it where everyone else puts theirs

Obvious levels attract stops, and clusters of stops attract the moves that trigger them. A stop exactly at the round number, or exactly at the swing low everyone can see, sits in the most likely place to be swept.

The fix is not to abandon the level — it is the right level — but to give it room. Slightly beyond the obvious point, so that a wick through does not close you while a genuine break does.

This costs you: a wider stop is a smaller position for the same risk. That is the correct trade, and it is worth making deliberately rather than discovering after a sequence of stop-outs that all reversed.

What not to do

Do not widen it mid-trade. This is the one that does lasting damage. It converts the trade into a different one with a larger loss than you approved, and it corrupts your records — an R computed against a moved stop is not comparable to anything, as covered in what is an R multiple. If you find yourself widening often, the stops are going too close to entry in the first place.

Do not tighten it to permit a larger position. See why tight stops can cost more: you have not reduced risk, you have raised how often you take the full loss, and you have increased the notional that fees and slippage are charged on.

Do not trade without one because “I will watch it”. Attention is not a control. It fails exactly when you need it, and it cannot be evaluated by a machine before an order goes out.

Do not use a limit order as a stop. In a gap it does not execute and you remain in the position — see slippage and market impact.

Moving it in the right direction

Tightening a stop as a trade works is a different action from widening one as it fails. Moving a stop to break-even, or trailing it behind structure, reduces risk and is legitimate.

Two things worth knowing. It converts some winners into scratches, which lowers your average win in R — a real cost that shows up in expectancy rather than in the win rate. And a trailing stop is still a stop: it belongs behind a level that would invalidate the continuation, not at a fixed distance chosen for comfort.

FAQ

Where should I place my stop-loss?

At the price where the reason you entered stops being true — a broken structure, a lost level, a volatility threshold appropriate to the setup. That level is a property of the market and does not depend on your account size. Once it is chosen, your risk percentage determines the position size rather than the other way round.

How do I decide stop distance and position size together?

You do not decide them together. The stop comes from the chart, the risk percentage comes from your own tolerance and is set in advance, and the position size is what those two imply. If the resulting size is uncomfortable, lower the risk percentage — moving the stop to fix the size breaks the only thing that made the stop meaningful.

Is it ever right to move a stop?

Tightening as a trade works is fine, and trailing behind structure is a normal technique. Widening as a trade fails is not — it enlarges a loss you already approved and makes your recorded R multiples incomparable. The asymmetry is the rule: stops may move in the direction that reduces risk.

Should my stop be at the obvious level?

Near it, usually just beyond it. Obvious levels are where stops cluster and clusters attract the moves that trigger them, so sitting exactly on one invites being swept by a wick that then reverses. Giving it a little room costs you position size, which is the correct price for not being stopped out of trades that were right.