ATR (14)
Average True Range
💡 What is ATR (14)? - The Thermometer of Volatility
ATR stands for Average True Range. It is a technical indicator that shows, as a number, how much a stock's price moves on average in a single day. To put it simply, ATR is like a "thermometer" for the stock market. Just as a person's body temperature being far from 98.6°F signals something is wrong, when a stock's ATR rises well above its usual level, it's a sign that something big is happening in the market.
Key Terms: Korean to English
ATR (Average True Range) | Volatility | True Range | High | Low | Previous Close | 14-Period | Stop Loss | Position Sizing
The number 14 after ATR means a 14-day average. So ATR(14) is the average of the daily price ranges over the most recent 14 trading days. This indicator was developed in 1978 by technical analysis pioneer J. Welles Wilder Jr. It was originally created for use in the commodities (raw materials) market, but it is now widely used in nearly all financial markets, including stocks, ETFs, and cryptocurrencies.
There is a common misunderstanding among beginner investors. ATR is not an indicator that tells you the direction of price movement (whether it will go up or down). ATR only tells you "how much" something moves. A high ATR means the price swings a lot; a low ATR means the price moves quietly. You have to judge the direction separately.
📐 How to Calculate ATR
To understand ATR, you first need to know the True Range. True Range is the largest of the following three values:
Step 1: Calculate True Range
The True Range is the largest of the following three values:
(1) Today's High - Today's Low
(2) |Today's High - Yesterday's Close| (absolute value)
(3) |Today's Low - Yesterday's Close| (absolute value)
Step 2: Calculate the 14-Day Average
ATR(14) = Average of the True Range values from the most recent 14 trading days
In practice, an Exponential Moving Average (EMA) method is used, which gives more weight to recent data.
For example, if Apple (AAPL) is currently trading at $175 and its ATR(14) is $3.50, this means Apple stock has moved an average of about $3.50 (roughly 2%) per day over the most recent 14 trading days. On the other hand, if Tesla (TSLA) is at $250 and its ATR(14) is $12.00, Tesla moves an average of $12 (about 4.8%) per day, making it a far more volatile stock than Apple.
You might wonder why we include the previous day's closing price rather than just looking at the difference between the high and low. The reason is to account for gaps that occur at the next day's open when news breaks after the market closes. For example, if yesterday's close was $100, and today the stock opened at $110 after earnings (with a high of $115 and a low of $108), the simple high-low range is $7, but the True Range is $15 (115 - 100). This way, the volatility that investors actually feel is reflected more accurately.
📊 How to Interpret ATR
Low ATR (Low Volatility)
This is when the ATR-as-a-percentage-of-price ratio is 1% or less. You often see this in large blue-chip stocks like Coca-Cola (KO) or Procter & Gamble (PG). Because the price moves steadily, it suits conservative investors, but it is hard to expect large gains. However, when a low ATR persists for a long time, it can also be a signal that a big move (breakout) is about to come.
Medium ATR (Moderate Volatility)
This is when the ATR-as-a-percentage-of-price ratio is around 1% to 3%. This is commonly seen in large tech stocks like Apple (AAPL), Microsoft (MSFT), and Amazon (AMZN). It offers both reasonable profit opportunities and manageable risk, making it suitable for most investors.
High ATR (High Volatility)
This is when the ATR-as-a-percentage-of-price ratio is 3% or more. This frequently appears in high-growth tech stocks like Tesla (TSLA) and NVIDIA (NVDA), as well as in small-cap stocks. There are opportunities for big gains, but the risk of loss is just as large. ATR often spikes during earnings season or times of sudden market shifts, so caution is needed.
The trend of ATR itself is also important. If ATR is trending upward, market volatility is expanding; if it is trending downward, volatility is shrinking. Generally, in down markets, fear drives ATR sharply higher, while in up markets, ATR tends to stay stable. During the March 2020 COVID crash, the S&P 500's ATR surged to 4 to 5 times its usual level.
🔄 Comparison with Similar Indicators
ATR vs Bollinger Bands
Both measure volatility, but in different ways. ATR uses the daily price range, while Bollinger Bands use the standard deviation of closing prices. ATR focuses on the size of a day's movement; Bollinger Bands focus on how far the price has drifted from its average. Using both together gives a more multidimensional analysis of volatility.
ATR vs VIX (Fear Index)
VIX is the expected volatility of the overall market, calculated from S&P 500 option prices, while ATR measures the actual past volatility of an individual stock. VIX is strongly forward-looking; ATR is based on past facts. ATR is better suited for analyzing individual stocks, while VIX is better for gauging the mood of the overall market.
ATR vs Beta
Beta measures a stock's volatility relative to the market (S&P 500), while ATR measures the absolute price range. A Beta of 1.5 means the stock moves 1.5% for every 1% move in the market, but you can't tell the actual dollar amount of volatility. ATR shows the volatility in real dollar terms, making it more useful for practical trading, such as setting stop-loss levels.
🎯 Practical Strategies
Practical use is far more important than theory when it comes to ATR. Below are common ways to use ATR in real investing.
Strategy 1: ATR-Based Stop-Loss Placement
This is the most widely used method. Set your stop-loss price by subtracting 1.5 to 3 times the ATR from your buy price. For example, if you bought NVIDIA (NVDA) at $500 and the ATR is $15, your stop-loss would be set at 500 - (15 × 2) = $470. This way, you avoid being stopped out by normal daily movement, but you still get out if a real downtrend begins. The higher the ATR multiple, the more conservative your approach; the lower the multiple, the more aggressive.
Strategy 2: Position Sizing
Buy less of high-ATR stocks and more of low-ATR stocks so that risk is balanced evenly. For example, suppose you have $10,000 to invest and want to limit your maximum loss per stock to $500: If Coca-Cola (KO) has an ATR of $1 and you set a 2× ATR stop, your risk per share is $2, so you can buy about 250 shares. If Tesla (TSLA) has an ATR of $12 and you set a 2× ATR stop, your risk per share is $24, so you can buy about 14 shares. This way, no matter which stock, you lose about the same dollar amount when stopped out.
Strategy 3: Breakout Confirmation Filter
When price breaks above a resistance line, check whether the move is at least 1× ATR. For example, if Amazon (AMZN) breaks through a $150 resistance line and the ATR is $5, the price must rise above $155 (resistance + 1 ATR) for it to count as a true breakout. Breakouts that are less than 1× ATR are likely to be false breakouts, so be careful. This approach can help you avoid many traps.
Strategy 4: Catching Explosions After Volatility Contraction
When ATR has been steadily declining and then suddenly surges, a new trend may be starting. This is called a "Volatility Squeeze." It's like pressing down a spring and then releasing it. A classic example is when ATR shrinks before earnings and then spikes right after the announcement. Rather than trying to predict the direction in advance, it's safer to wait for the breakout direction to confirm before entering.
Strategy 5: Trailing Stop (Chandelier Exit)
This is a method of raising your stop-loss along with the price as it goes up. Continuously update the stop-loss by subtracting 3× ATR from the highest price reached. For example, if JP Morgan (JPM) keeps rising after you bought it and hits a high of $160 with an ATR of $3, you raise your stop-loss to 160 - (3 × 3) = $151. This lets you preserve profits while staying in the position as long as the trend continues. This is the famous "Chandelier Exit" strategy.
🏭 ATR Characteristics by Sector
ATR varies greatly by sector. Even the same ATR number can mean very different things depending on the sector, so you should always compare stocks within the same sector.
Technology
Tech stocks generally have high ATR ratios because expectations for growth cause large price swings. Stocks like NVIDIA (NVDA), Tesla (TSLA), and AMD can have ATR ratios of 3% to 5%. They tend to be highly sensitive to tech innovation news and competitor announcements.
Utilities / Consumer Staples
These are the sectors with the lowest ATR ratios. Stocks like Coca-Cola (KO), Johnson & Johnson (JNJ), and NextEra Energy (NEE) often have ATR ratios below 1%. Stable earnings structures and dividends lead to small price movements.
Financials
Sensitive to interest rate changes, financials show a moderate level of ATR. Large banks like JPMorgan (JPM) and Bank of America (BAC) can see ATR spikes during Fed rate decisions or major economic data releases. During financial crises, ATR can climb to 3 to 4 times its normal level.
Biotech / Pharma
In this sector, ATR can swing extremely based on FDA approvals and clinical trial results. A stock might show low ATR most of the time, then jump more than 10-fold on the day clinical results are released. This tendency is stronger in smaller biotech stocks.
⚠️ Cautions When Using ATR
1. It does not show direction: A high ATR does not mean the price will go up. ATR only shows the size of the movement. Direction should be judged using other indicators (moving averages, MACD, etc.) alongside it.
2. Don't compare absolute values directly: For a $500 stock, an ATR of $10 (2%) and for a $50 stock, an ATR of $5 (10%) — the latter is far more volatile. Always compare using the ratio of ATR to price (ATR %).
3. It is based on past data: ATR is calculated from the past 14 days of data, so it does not guarantee the future. Especially around major events like earnings releases or rate decisions, ATR can change dramatically.
4. Stocks with low trading volume can be distorted: Stocks with very low daily trading volume can have their ATR pushed abnormally high by one or two large trades. The ATR of small-cap stocks is less reliable, so always check the trading volume, too.
5. The 14-day period is not absolute: Short-term traders sometimes use ATR(7), while long-term investors may use ATR(21) or ATR(50). Adjust the period to fit your own investment horizon.
✅ ATR Usage Checklist
☑ Did you divide the ATR by the price to check it as a ratio (%)?
☑ Did you compare the ATR ratio with other stocks in the same sector?
☑ Did you check the trend of ATR (rising / falling / sideways)?
☑ Did you set your stop-loss based on ATR?
☑ Did you figure out why ATR is abnormally high or low?
☑ Did you use other indicators together to judge direction?
☑ Did you adjust your position size according to ATR?
☑ Did you check the schedule of major events (earnings, FOMC, etc.)?
❓ Frequently Asked Questions (FAQ)
Q. Does a high ATR mean the stock is always risky?
A. Not necessarily. A high ATR simply means the volatility is large; it is not the same as saying it is risky. Stocks like Tesla (TSLA) and NVIDIA (NVDA) have high ATRs but have also produced big long-term gains. That said, a high ATR does mean you can experience large losses in a short period, so you should reduce your position size and set strict stop-losses. Many investors actually use volatility itself as an opportunity.
Q. Can I use a different period instead of ATR(14)?
A. Of course. 14 is just the default recommended by its developer, Wilder. Day traders prefer ATR(7) or ATR(5); swing traders often use ATR(10) to ATR(14); long-term investors sometimes use ATR(21) or ATR(50). The shorter the period, the more sensitive it is to recent volatility; the longer the period, the more stable it is but the slower it reacts to change. It's important to choose a period that matches your own trading cycle.
Q. Can I use ATR to time my buys and sells?
A. It's difficult to time buys and sells using ATR alone, because ATR only tells you the size of volatility. But combined with other indicators, it becomes very useful. For example, when a moving-average golden cross happens and ATR is low, you can interpret it as "a big move higher may be coming"; when RSI is overbought and ATR spikes, you can judge that "a trend reversal may be near."
Q. Should long-term investors also look at ATR?
A. ATR is useful for long-term investors, too. First, when timing staggered purchases, you can invest smaller amounts more frequently during high-ATR periods when movement is large, and invest larger lump sums during low-ATR periods. Second, when rebalancing your portfolio, you can use ATR to help reduce the weight of stocks whose volatility has become excessively high. Third, an abnormally high ATR signals market anxiety, and can be used as a signal to consider holding more cash.
🇰🇷 Notes for Korean Investors
Exchange Rate Impact: When investing in U.S. stocks from Korea, ATR is measured in U.S. dollars. When converted to Korean won, the actual volatility you feel can be larger because of exchange-rate fluctuations. During periods when the won-dollar exchange rate is unstable, stock-price volatility and exchange-rate volatility act on you at the same time.
Time Zone Difference: The U.S. stock market opens at 11:30 PM Korean time (10:30 PM during U.S. daylight saving time). If major news breaks in the early Korean morning, a large gap can occur at the next market open, causing ATR to spike. Korean investors are advised to set stop-losses a bit wider (ATR × 2.5 to 3).
Tax Considerations: Capital gains tax on U.S. stocks is 22% (including local tax), with an annual exemption of 2.5 million KRW. If you frequently trade high-ATR stocks, the tax burden can grow, so consider reducing the number of short-term trades.
Using Domestic Brokerages: Most Korean brokerages' MTS/HTS platforms offer ATR charts. At Kiwoom Securities, Mirae Asset, and others, you can add ATR(14) from the technical indicator settings. You can also check ATR for free on overseas sites like Finviz or TradingView.