Indicator: What Is ATR? Sizing Stop Losses to Volatility

ATR (Average True Range) is different from every other indicator in this series — it doesn't tell you direction, and it doesn't give you a buy or sell signal. It measures one thing only: how much price is moving, on average, over a recent period. That makes it one of the most useful tools for sizing a Stop Loss correctly.

What ATR Measures

ATR calculates the average "true range" over a set number of candles, usually 14. The true range of each candle is the greatest of:

1. Current high minus current low (the candle's own size),
2. Current high minus the previous close, or
3. Current low minus the previous close.

The second and third cases exist to capture gaps — if price opens far from yesterday's close, the candle itself might look small while the actual move was large, and true range counts that. A rising ATR means candles are getting bigger — the market is more volatile. A falling ATR means candles are shrinking — the market is calming down.

Two properties worth internalizing:

• ATR is absolute, not relative. An ATR of 0.0080 on EUR/USD (80 pips) means nothing next to an ATR of 1.20 on USD/JPY until you convert both into pips or percent — it can't be compared across pairs directly.
• ATR scales with timeframe. The same pair might show 12 pips of ATR on M15 and 90 pips on D1. Always read ATR on the timeframe you're actually trading.

Using ATR to Size a Stop Loss

Instead of picking a fixed pip distance for every Stop Loss (say, always 20 pips), many traders set it as a multiple of ATR, commonly 1.5x to 2x ATR:

• If ATR is 15 pips, a 2x ATR stop is placed 30 pips away.
• If ATR rises to 40 pips because the market got more volatile, the same 2x rule now places the stop 80 pips away.

This keeps the stop at a distance that matches current market behavior — tight during quiet periods, wider during volatile ones — instead of getting stopped out by normal noise on a volatile day, or leaving unnecessary room on a quiet one. The underlying idea: a stop inside the market's average daily wiggle isn't a decision point, it's a coin flip — ATR tells you where "normal noise" ends so the stop only triggers when something actually went wrong.

Worked Example: ATR + Risk % Together

This is where ATR connects to Risk Management Basics — the two rules compose into a complete sizing method:

1. Account: $10,000, risking 1% = $100 per trade.
2. Chart: EUR/USD H4, ATR currently 30 pips. Using a 2x ATR stop = 60 pips.
3. Size: $100 ÷ 60 pips ≈ $1.66/pip → about 0.16 lots.

A month later the market is quieter — ATR is 15 pips, so the stop is 30 pips and the same $100 risk allows 0.33 lots. The dollar risk never changed; the position size breathed with volatility. This is how a single strategy stays consistent across calm and chaotic market regimes.

Other Common Uses

• Take Profit distances — expressing targets in ATR multiples (e.g. stop at 1.5x, target at 3x ATR) keeps the Risk:Reward geometry constant across conditions, and sanity-checks ambition: a 200-pip target on a pair moving 20 pips a day is a multi-week hold, whether or not you meant it to be.
• Trailing stops — a stop that trails price by a multiple of ATR (the well-known "Chandelier Exit" trails 3x ATR below the highest high since entry), staying wide in volatile stretches and tightening as the market calms.
• Filtering setups — some traders avoid entering new trades when ATR is unusually low (a sign the market may be about to squeeze into a bigger move — the same volatility-cycle logic as the Bollinger Band squeeze) or unusually high (a sign of an already-extended, possibly exhausted move).
• Regime awareness — a glance at ATR answers "is this market currently calm or wild?", which should influence size and expectations before any directional analysis starts.

A Word of Caution

ATR is a lagging average, calculated from what already happened — it doesn't predict a volatility spike before it occurs (like a major news release; that's what the Economic Calendar is for). After a one-off shock, ATR also stays elevated for a while even once the market has calmed, since the spike remains inside the 14-candle average until it rolls out. And ATR says nothing about direction — a soaring ATR is equally consistent with a crash and a rally — so it's normally used alongside a trend/range read (see Trend vs Range) rather than as a standalone signal.

Download the Indicator

This custom indicator plots ATR in a separate window, useful for reading the current value to plug into your Stop Loss and position-size calculations. It's available for both MetaTrader 4 and MetaTrader 5 below.

How to Install — MetaTrader 4

1. Download the atr-alert.mq4 file below.
2. Open MetaTrader 4 → click File → Open Data Folder.
3. Place the file in the MQL4/Indicators folder.
4. Restart MetaTrader 4, then drag the indicator from the Navigator window onto the chart.

How to Install — MetaTrader 5

1. Download the atr-alert.mq5 file below.
2. Open MetaTrader 5 → click File → Open Data Folder.
3. Place the file in the MQL5/Indicators folder.
4. Restart MetaTrader 5, then drag the indicator from the Navigator window onto the chart.

Both files are source code — open and review the full code before using it, for your own safety.