Orders & execution · Beginner

Stop-Loss Orders Explained

A stop-loss is not mainly protection. It is the number that makes position sizing possible at all, which is why the trade cannot be sized without one.

Last reviewed 15 September 2026 by the MarketPro research desk · Editorial policy

In short

A stop-loss order automatically closes a position once price reaches a level you set in advance, converting an open-ended exposure into a known, sized risk. Once triggered it becomes a market order, so it starts the exit at your level but does not guarantee the fill price. In gaps, halts or fast news it can fill well beyond the level, so size the position for a worse-than-planned exit.

What to remember

Without a stop there is no denominator, so there is no position size. That is the stop's main job, not the protection.
A triggered stop becomes a market order. It starts the exit at your level, it does not fill at it.
A 15-pip stop on a pair with a 60-pip daily ATR is inside the noise and will be hit by nothing in particular.
Choosing the stop distance to justify a position size you already wanted is how a 1% rule becomes a 4% loss.

Lesson 2 of 16 in Orders and execution

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A 30-pip stop, priced before you click

A stop-loss order sits dormant at the broker and closes the position if price reaches a level you named before you entered. Its real value is not that it saves you from a bad trade. It is that it converts an open-ended exposure into a number you can size against before you enter.

Work it through. You have a $5,000 account and you have decided a single trade may cost 1%, so $50. You want to buy EUR/USD at 1.0850 with a stop at 1.0820, which is 30 pips. At $10 a pip per standard lot, $50 of risk divided by 30 pips gives $1.67 a pip, so the position is 0.17 lots. If the stop fills as expected, the trade costs $50. If you had placed the stop at 1.0790, 60 pips away, the same $50 of risk buys half the size.

Notice which number moved. The risk stayed at $50 and the position size absorbed the wider stop. That is the point of the order: without a defined stop there is no denominator, so there is no way to calculate a position size at all. The position size calculator does the division for any pair and account currency.

What happens the moment the stop level trades

A standard stop-loss sits dormant at the broker until price touches your level. At that moment it becomes a market order, and a market order takes the best price then available. In a normal session on a major pair, that is your level give or take a fraction of a pip. In a fast market it can be materially worse, and the difference is slippage.

So a stop is not a promise to exit at the price on the ticket. It is a promise to start exiting at that price. That distinction is invisible for months and then arrives all at once on a central bank surprise. Sizing so that a stop fill 10 or 20 pips beyond your level is survivable, rather than assuming the exact number, is the honest way to hold the position.

Placing the level: noise, structure and ATR

There are three defensible ways to choose the level, and one indefensible one.

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Structure. Below the swing low that the trade depends on, plus a buffer. If price trades there, the reason you entered has stopped being true, which is the cleanest possible exit trigger.
Volatility. A multiple of average true range, commonly 1.5 to 2 times the ATR of your timeframe. On a pair with a 60-pip daily ATR, a 15-pip stop is inside the ordinary daily wiggle and will be hit by nothing in particular.
A fixed percentage or cash figure. Simple, and blind to the chart. It works only if you then size the position to it rather than the other way around.
The indefensible one: choosing the stop distance to justify the position size you already wanted. That is how a 1% rule becomes a 4% loss.

Too tight and normal intraday noise removes you from trades that would have worked. Too wide and a single loss costs more than planned, unless you cut the size to match, which most people forget to do.

The weekend gap that fills you 60 pips lower

A stop does not protect against every scenario, and the exceptions are worth naming plainly:

Gaps. If a pair closes Friday at 1.0850 and opens Sunday at 1.0760, a stop at 1.0820 triggers at the open and fills near 1.0760. The loss is three times the planned one.
Halts and suspensions. In equities a trading halt can freeze the instrument entirely, and the stop executes only when trading resumes, at whatever price that is.
Liquidity holes. Around a surprise rate decision the book can empty for a few seconds, and your market order walks down it.
Broker-side execution. Stop orders held at the broker rather than the exchange are filled on that broker's price feed, which is one more reason to size for a poor fill rather than a perfect one.

None of this argues against using stops. It argues against treating the number on the ticket as a floor. Run a few of these scenarios through the drawdown calculator and you can see what a run of worse-than-planned exits does to an account.

Deciding the exit while you have no position

The practical discipline is boring and it is most of the value. Choose the stop level before the order goes in, put it in the same ticket as the entry, and treat moving it further away as a rule violation rather than a judgement call. The moment you own the position, your assessment of that level is no longer independent: you now have a reason to want it to be wrong.

A mental stop is not a stop. It is an intention, and it fails at exactly the moment it is needed, because that is the moment you are most invested in being right. If your platform supports attaching a stop at entry, use it every time, and write the level in your journal alongside the reason it is there. Our page on risk rules covers how per-trade stops interact with daily limits and drawdown, which is where the real account protection comes from.

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Written and reviewed by the MarketPro research desk

MarketPro is a trading-signal and trading-education app operated by Harajuku Holdings LTD (Cyprus). Our signal desk publishes and tracks every trade idea in-app, and every page here is checked against the app's live behaviour before publishing. Last reviewed 15 September 2026. How we produce signals and content · About MarketPro

FAQ

Stop-Loss Orders Explained: questions

Does a stop-loss guarantee I exit at that price?

No. A standard stop becomes a market order the moment your level trades, so it guarantees that the exit begins there, not that it completes there. In normal conditions on a major pair the difference is a fraction of a pip. Across a weekend gap, a halt or a surprise central bank decision the fill can be many pips worse, which is why the position should be sized to survive a poor fill.

How far away should I set my stop-loss?

Far enough that ordinary noise on your timeframe does not reach it, which usually means below the structural level the trade depends on, or roughly 1.5 to 2 times the current ATR. Then set the position size from that distance rather than picking a size first. The distance is decided by the chart and the volatility, and the size is what adjusts.

Is a mental stop as good as a real stop order?

No, because it fails at the moment it is needed. A mental stop requires you to act decisively while you are holding a losing position and are most motivated to wait for a recovery. A resting order does not consult you. It also works while you are asleep, offline or away from the screen, which is when a large part of overnight and weekend risk actually arrives.

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