About the ATR Calculator
Average true range (ATR) is J. Welles Wilder’s measure of how much a market typically moves in one bar, including overnight gaps. This ATR calculator takes a list of high, low and close prices, works out the true range of every bar and smooths it with Wilder’s method over the period you choose (14 is the standard). It then turns the ATR into practical numbers: ATR as a percentage of the latest close, a stop distance of a chosen ATR multiple, long and short stop prices, and how many shares fit a fixed money risk.
It is for swing and day traders who place stops outside normal noise, trend followers sizing positions by volatility, and anyone checking the ATR shown on a charting platform. Paste one bar per line as “high, low, close”, oldest first; extra leading columns such as a date or open are ignored as long as the last three numbers are high, low and close.
The first bar’s true range is its high minus low. The first ATR is the simple average of the first N true ranges, and each later ATR is Wilder-smoothed. If you supply fewer bars than the period, the calculator uses the simple average of the bars available, and early values will differ slightly from a platform that has a longer history.
With the default inputs, the average true range is 2.1276. Change any value above to recalculate instantly.
How to use the atr calculator
- 1Export or copy high, low and close prices, one bar per line, oldest first.
- 2Paste them into the price box (dates or opens in front are ignored).
- 3Set the ATR period, typically 14.
- 4Choose a stop multiple such as 1.5× or 2× ATR and the money you will risk.
- 5Use the stop prices and position size to plan the trade.
Formula and method
True range extends the simple high-low range to include gaps: if a market opens far above or below the previous close, that distance counts as part of the bar’s range. Wilder’s ATR seeds with the simple average of the first n true ranges and then applies his smoothing, which is an exponential moving average with a smoothing factor of 1/n, so each new bar has a weight of 1/n.
The stop distance is the ATR multiplied by your chosen multiple; the long stop is the last close minus that distance and the short stop is the last close plus it. Position size is the money you are willing to lose divided by the stop distance, rounded down to whole shares.
- TR
- True range of a bar
- n
- ATR period (bars)
- ATR
- Average true range
- PrevClose
- Close of the previous bar
Worked examples
14-period ATR on 15 daily bars, 2× ATR stop
The first 14 true ranges average 2.1143; the 15th bar’s true range of 2.30 is Wilder-smoothed in to give an ATR of 2.1276, about 2.07% of the $102.90 close. A 2× stop is 4.26 away, so a long stop sits at $98.64 and $500 of risk buys 117 shares.
Shorter 5-period ATR, 1.5× stop
With a 5-bar period the ATR reacts faster and ends at 2.1152. A 1.5× ATR stop is 3.17 below the close at $99.73, and $500 of risk allows 157 shares.
Only three bars available
True ranges are 2.0, 2.5 and 2.5, so with fewer bars than the 14-bar period the ATR is their simple average, 2.333. A 2× stop is 4.67 below the $51 close, allowing 214 shares for $1,000 of risk.
Frequently asked questions
What is a good ATR value?+
There is no universally good value; ATR is in price units and depends on the asset’s price and volatility. Divide ATR by the price to compare markets: an ATR of 2% of price means a typical daily move of about 2%.
How do I use ATR for a stop loss?+
Place the stop a multiple of ATR away from your entry, commonly 1.5 to 3 times, so normal daily noise is unlikely to trigger it. For a long trade, stop = entry − multiple × ATR; for a short, stop = entry + multiple × ATR.
Why does my charting platform show a slightly different ATR?+
Platforms differ in how they seed the first value and some use a simple or exponential moving average instead of Wilder smoothing. With a long price history the Wilder values converge, but short samples can differ in the second decimal.
What period should I use for ATR?+
Wilder used 14 periods, which remains the default on most platforms. Shorter periods such as 5 to 10 react faster to changes in volatility; longer periods such as 20 to 50 give a steadier figure for position sizing.
Does ATR show trend direction?+
No. ATR measures only the size of price moves, not their direction. A rising ATR means volatility is increasing, which can happen in strong rallies as well as sell-offs.
Results are estimates for educational purposes and are not financial advice. Rates, fees and terms vary — confirm with your lender or a licensed advisor before making decisions.