Average true range calculator
ATR shows how far a market usually travels in a day, which makes it the natural starting point for stops and trade size. Paste daily highs, lows and closes, pick a period and an averaging method, and the calculator finds the true range of every bar and the latest ATR. It then turns that ATR into stop levels and a position size that risks the amount you set.
True range and ATR across your data
Every bar's true range with the smoother ATR line on top. An ATR that is climbing means volatility is increasing.
Latest bars
The most recent bars with their true range and ATR.
| Date | High | Low | Close | True range | ATR |
|---|
How ATR is calculated
By default the calculator uses Welles Wilder's original method, and a simple moving average is available as an alternative.
True range
The largest of three distances, so overnight gaps are included.
TR = max(high − low, |high − previous close|, |low − previous close|)
First ATR
A simple average of the first N true ranges.
ATRN = average of TR1 to TRN
Wilder smoothing
Every later ATR mixes the previous value with the newest true range.
ATR = (previous ATR × (N − 1) + TR) ÷ N
Stop levels
Your chosen multiple of ATR away from the latest close.
long stop = close − multiple × ATR
Position size
The number of units that makes the stop cost your risk amount.
units = risk ÷ (multiple × ATR)
Average true range FAQ
What is average true range?
ATR measures how much a market typically moves in one bar, normally a day. It averages the true range, the largest of three distances: today's high to low, today's high to yesterday's close, and today's low to yesterday's close. Including gaps from the previous close is what makes it "true".
How do you calculate ATR?
Find the true range for each bar and average it over a period, usually 14 bars. Welles Wilder, who invented ATR, used a smoothed average: the previous ATR times 13, plus the new true range, divided by 14. A plain average of the last 14 true ranges is a common alternative.
What do traders use ATR for?
Mostly stops and position size. A stop two ATRs away sits outside most ordinary daily movement, and sizing so a two-ATR move costs a fixed amount keeps risk steady in calm and wild markets alike. ATR does not predict direction, only typical distance.
Which ATR period should I use?
14 is the standard. A shorter period such as 7 reacts faster to changes in volatility, while 20 or 50 is smoother. Stick with one period so stops and sizes stay comparable over time.
What counts as a good ATR?
There is no good or bad ATR, only more or less volatility. Expressing ATR as a percentage of price lets you compare markets: a stock with ATR at 4 percent of its price moves twice as much, relative to price, as one at 2 percent.
How should my price data be formatted?
Put each bar on its own line as high, low and close, oldest first, split by commas or tabs. A date at the start of each line is optional. You need at least one more bar than the ATR period for a complete reading.