Average True Range Percent (ATRP) expresses the Average True Range (ATR) indicator as a percentage of a bar’s closing price. ATRP is used to measure volatility just as the Average True Range (ATR) indicator is. ATRP allows securities to be compared, where ATR does not.
ATR measures volatility at an absolute level, meaning lower priced stock will have lower ATR values than higher price stocks. ATRP displays the indicator as a percentage, to allow for securities trading at different prices per share to be compared.