A stop loss is a price you choose before the trade. If the market reaches it, the trade closes automatically. For a long trade the stop sits below your entry; for a short trade it sits above.
It is the most important order in trading, and the most misused. This article explains how a stop loss works, three ways to decide where it goes, how to turn it into the right position size, and why moving it after entry is the habit that costs traders the most.
How a stop loss order works
You buy EURUSD at 1.0850 and set a stop at 1.0830. Nothing happens while the price stays above 1.0830. If the price touches 1.0830, the platform sends a market order to sell, and the trade closes near that price.
Two things to know:
- The fill can be a little worse than your level in a fast market. This is slippage, and it is normal.
- A stop loss does not make you a worse trader. Getting stopped out is part of a plan that works. A trade without a stop is the thing that ends accounts.
What a stop loss is really for
Most beginners think the stop loss is a guess about where the trade is wrong. That is half of it. The other half is more useful: the stop defines your risk, and your risk defines your size.
If you know your stop is 20 pips away and you want to risk 100 dollars, you know exactly how big the trade can be. Without a stop, "how much can I lose" has no answer, and no position size is right.
Three ways to decide where the stop goes
1. Structure
Put the stop where the idea is wrong. For a long trade off a support level, the stop goes a little below that level. If the price goes there, the reason for the trade is gone. This is the method most experienced traders use, because the stop has a meaning.
2. Volatility (ATR)
The Average True Range tells you how much the market moves in a normal bar. A stop of 1.5 to 2 times the ATR gives the trade room for normal noise. This method is simple and adapts to the market: wider stops in wild markets, tighter stops in quiet ones.
3. A fixed distance or percent
A stop always 10 pips away, or 1 percent below entry. Easy to apply and easy to test. The weakness is that the market does not care about your 10 pips: in a volatile hour it will touch them by chance.
A good habit is to combine them: choose the level by structure, check that it is at least one ATR away, and if it is not, skip the trade or wait for a better entry.
From stop to position size
This is the step that connects the stop loss to your account.
- Decide your risk per trade in money. For example 1 percent of a 10,000 dollar account = 100 dollars.
- Measure the stop distance. For example 20 pips.
- Divide: 100 dollars / 20 pips = 5 dollars per pip, which on EURUSD is 0.5 lots.
A wider stop means a smaller position, not a bigger loss. Traders who skip this step risk 50 dollars on one trade and 400 on the next without noticing. A journal shows this quickly: if your losses are all different sizes, your sizing is not based on the stop.
The mistake that costs the most: moving the stop
The price comes close to your stop. You move the stop further away "to give it room". The price keeps going. Now the loss is twice the plan.
Moving the stop is the single most expensive habit in most journals, because it turns small planned losses into large unplanned ones. It feels like patience. It is not; the plan already included the room.
The fix is simple to say and hard to do: the stop can move only toward the profit, never away from it. Write it as a rule and tag every trade where you broke it. When you see the total cost of moved stops in a month, the habit usually ends on its own. Here is what moved stops and other mistakes cost.
Trailing stops and breakeven stops
A trailing stop follows the price as the trade moves in your favour, at a fixed distance. It locks in profit without you watching. The risk is trailing too tight and getting stopped out on normal noise.
A breakeven stop moves the stop to your entry once the trade is some distance in profit. It feels safe, but done too early it turns many winners into zero trades. Look at your journal: if a lot of your trades close at breakeven and the price went on to the target afterwards, your breakeven rule is too early.
Common questions about stop loss placement
Too tight. A stop inside the normal noise of the market gets hit by chance. If your win rate is far below what your setup should give, tight stops are a common reason.
Too wide. A stop that is far away "to be safe" makes your position tiny and your R multiples small. The stop should be where the idea is wrong, not as far as possible.
No stop, mental stop. A mental stop is a plan to close the trade by hand. In practice it is a plan to not close the trade. Use a real order.
Frequently asked questions
Should every trade have a stop loss?
Yes. A stop loss is how you know your risk, and your risk is how you know your size. A trade with no stop has no defined risk, so no position size is correct.
Does a stop loss guarantee my maximum loss?
Almost. In a fast market or a gap, the stop can fill past your level. The difference is slippage. Guaranteed stop losses exist at some brokers for an extra cost.
Where should a beginner put the stop loss?
Below the last swing low for a long trade, above the last swing high for a short, with a small buffer. Then check that the distance is at least one ATR of the timeframe you trade. Then size the position from that distance.
Is it ever OK to move the stop loss?
Toward your entry or toward profit, yes: that is how trailing and breakeven stops work. Away from your entry, no. Moving the stop away is the most expensive habit in most trading journals.
See what your stops really do
Your stop loss is a decision you make dozens of times a month. A journal shows whether you keep them, whether they are too tight, and what it costs when you move them. Start your journal free and tag the first moved stop.