Perhaps another way to look at it is “What is a reasonable profit expectation for my time frame and the instrument’s direction”?
Equities prices tend to drop 50% faster than they rise. Prices tend to stall at previous day’s, week’s, reaction high / low points, or a wide range bar. For a trending market, about a standard deviation move based on implied volatility is a reasonable exit point. For trading range days, 1/2 of a standard deviation move on either side of the open seems about right.
For day trading, an “Up day” could be considered those days when the instrument closes higher than its open and an “Down day” is when the price closes below its open. Either use a spreadsheet to calculate the average, or whatever other criteria you want to use, of the range of the up days by subtracting the open from the day’s high. Repeat the same process for down days for the average daily range according to market direction. In the alternative, you can use strike prices of calls and puts as day trading targets for options that expire at the end of the day. Use .16 delta for expected trend days or .30 delta for expected range days. If there are no options expiring on the current day, you can use the following formula: Underlying price*annual Implied volatility of calls for expected up days or puts for expected down days*Square root of (365 minus days to option expiration in calendar days).
about to trail stop out of 200 @ 20.65; I'm in 300