What Is the Average True Range (ATR) Indicator?
The Average True Range, or ATR, is a technical indicator that measures how much a stock’s price typically moves over a given period. It doesn’t tell you which direction a stock is heading, only how much it tends to swing, which makes it a pure measure of volatility.
Volatility just means how much and how fast a price moves up and down. A stock that jumps around a lot has high volatility. A stock that barely moves has low volatility. ATR turns that idea into a single number you can track on a chart.
Who Created the ATR Indicator?
Welles Wilder, a mechanical engineer turned trader, introduced the ATR in his 1978 book “New Concepts in Technical Trading Systems.” He also created other well-known tools like the RSI and the ADX. Wilder originally designed ATR for commodities, which often had large overnight price gaps, but it’s now used across nearly every type of market.
How Is ATR Calculated?
ATR starts with something called the “true range,” which captures the full extent of a price move in a single period, including any gaps. The true range for a given day is the largest of these three values:
- The current high minus the current low
- The current high minus the previous close (absolute value)
- The current low minus the previous close (absolute value)
Once you have the true range for each period, ATR is simply a moving average of those values, typically over 14 periods. So a 14-day ATR is the average true range over the last 14 trading days.
You don’t need to calculate this by hand. Every charting platform plots ATR automatically as a line below the price chart, usually shown as a dollar or point value.
What Does the ATR Number Actually Mean?
If a stock has an ATR of $2, that means, on average, the stock has moved about $2 from high to low each day over the measurement period. A higher ATR means bigger daily price swings. A lower ATR means calmer, more stable price action.
For example, a stock trading around $50 with an ATR of $1 is moving roughly 2% per day on average. A stock trading around $50 with an ATR of $5 is moving about 10% per day on average, which is a much wilder ride.
How Do Traders Use ATR?
Setting Stop-Loss Levels
One of the most common uses of ATR is setting a stop-loss, which is an order to automatically sell a position if it drops to a certain price, limiting your loss. Instead of picking a random stop distance, traders often set stops at a multiple of ATR, such as 2x ATR below the entry price. This adjusts the stop to the stock’s actual behavior rather than an arbitrary percentage.
For example, if a stock’s ATR is $1.50, a trader might place a stop 2x ATR, or $3, below their entry price. This gives the trade enough room to handle normal daily noise without getting stopped out too early.
Sizing Positions
Because ATR reflects how much a stock typically moves, some traders use it to decide how many shares to buy. A more volatile stock (higher ATR) might warrant a smaller position size, while a calmer stock (lower ATR) might allow for a larger position, keeping the dollar risk roughly consistent across trades.
Gauging Breakout Strength
A sudden jump in ATR can signal that a price move has real conviction behind it, such as during a breakout above resistance. A breakout on unusually low ATR, by contrast, might suggest weaker follow-through.
Comparing Volatility Across Time
Traders also watch how ATR changes over time for the same stock. Rising ATR suggests volatility is increasing, which can mean bigger opportunities but also bigger risks. Falling ATR suggests the stock is settling into a quieter period, sometimes before a bigger move (since periods of low volatility can precede sharp breakouts).
ATR Is Not a Directional Indicator
This is the most important thing to remember about ATR: it says nothing about whether price is going up or down. A stock can have a rising ATR while crashing, rallying, or moving sideways with wide daily swings. ATR only tells you the size of the moves, not their direction. That’s why it’s almost always used alongside trend or momentum tools like moving averages, RSI, or trendlines.
ATR Quick Reference
| ATR Behavior | What It Suggests |
|---|---|
| High and rising ATR | Increasing volatility, bigger price swings expected |
| Low and falling ATR | Decreasing volatility, calmer price action |
| Sudden ATR spike | Often tied to news, earnings, or a strong breakout |
| ATR used with stop-loss | Helps set stops based on typical price movement, not guesswork |
Key Takeaways
- ATR measures the average size of a stock’s price moves over a set period, usually 14 days.
- It’s a volatility indicator, not a directional one, so it doesn’t predict whether price will rise or fall.
- Traders commonly use ATR to set stop-loss distances and adjust position sizes.
- Rising ATR signals increasing volatility; falling ATR signals a calmer market.
- It works best paired with a trend or momentum indicator, since ATR alone doesn’t show direction.
FAQ
Is a high ATR good or bad?
Neither by itself. A high ATR just means bigger price swings, which can create more opportunity but also more risk. Whether that’s good or bad depends on your strategy and risk tolerance.
What is a good ATR multiplier for stop-loss orders?
Many traders start around 1.5x to 3x the ATR value, then adjust based on the stock’s behavior and their own risk tolerance. There’s no single correct multiplier for every situation.
Can ATR predict which direction a stock will move?
No. ATR only measures the magnitude of price movement, not its direction. You’d need a separate tool, like a moving average or trendline, to assess direction.
What’s a normal ATR value?
There’s no universal “normal” value, since it depends on the stock’s price and typical behavior. A better approach is comparing a stock’s current ATR to its own historical ATR range.
Does ATR work for day trading?
Yes, many day traders use shorter-period ATR settings on intraday charts to help size positions and set tighter, more realistic stop-loss levels for fast-moving trades.
