Average true range calculator
ATR tells you how far a market normally moves in a day, which is the starting point for sensible stops and position sizes. Paste your daily high, low and close prices, choose the period and averaging method, and this calculator works out the true range of every bar and the current ATR. It then turns the ATR into stop levels and a position size that risks the amount you choose.
True range and ATR over time
Each bar's true range and the ATR line that smooths it. A rising ATR means volatility is picking up.
Recent bars
The latest bars with their true range and ATR.
| Date | High | Low | Close | True range | ATR |
|---|
How ATR is calculated
The calculator follows Welles Wilder's original method by default, with a simple moving average as an option.
True range
The biggest of three distances, so overnight gaps count.
TR = max(high − low, |high − previous close|, |low − previous close|)
First ATR
The simple average of the first N true ranges.
ATRN = average of TR1 to TRN
Wilder smoothing
Each later ATR blends the old value with the new true range.
ATR = (previous ATR × (N − 1) + TR) ÷ N
Stops
Your multiple of ATR away from the last close.
long stop = close − multiple × ATR
Position size
Units that make the stop cost your risk amount.
units = risk ÷ (multiple × ATR)
ATR questions
What is the average true range?
ATR measures how much a market typically moves in one bar, usually one day. It averages the true range, which is 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. Counting gaps from the previous close is what makes it "true".
How is ATR calculated?
Work out the true range for each bar, then average it over a period, most often 14 bars. Welles Wilder, who created ATR, used a smoothed average: each new ATR is the previous ATR times 13, plus the new true range, divided by 14. A simple average of the last 14 true ranges is a common alternative.
What is ATR used for?
Mainly for stops and position sizing. A stop placed two ATRs away is outside most normal daily movement, and sizing so that a two-ATR move costs a fixed amount keeps risk the same across calm and volatile markets. ATR does not tell you which way price will go, only how far it tends to move.
What period should I use?
14 is the standard. A shorter period, such as 7, reacts faster to changes in volatility; a longer one, such as 20 or 50, is smoother. Use the same period consistently so your stops and sizes are comparable over time.
What is a good ATR?
There is no good or bad ATR, only higher or lower volatility. Comparing ATR with the price, as a percentage, lets you compare markets: a stock with ATR at 4 percent of its price moves twice as much, relative to its price, as one at 2 percent.
What format should my data be in?
One bar per line with high, low and close, oldest first, separated by commas or tabs. A date at the start of the line is optional. You need at least one more bar than the ATR period for a full reading.