After that, to achieve each subsequent average true range, you would multiply the previous 14-day ATR by 13, add the most recent day's true range, and then divide the result by 14. Interpreting the ...

The time period used for average true range calculations can vary. It’s common for ATR to be based on a security’s 14-day moving average, though the periods used can be shorter or longer.

From cityindex.com The average true range is a technical indicator that tells you a market’s current volatility – making it a key part of many successful strategies. Learn how to use the ATR indicator ...

Previous Close – Current Low: The range between the lowest price for the current period and the previous close. The ATR is the moving average of these true ranges over a set period, usually 14 days.