How to compute RSI for first 13 minutes (intraday)


As we know the formula for computing Relative Strength Index (RSI) = 100 - (100/(1+RS)) where RS is the relative strength (ratio of average gain and average loss). In general, the look-back period is 14 days. I want to know how to calculate RSI for intra-day. Is there a lookback period of 14 minutes for intra-day? If it is 14 minutes, then how to compute the RSI for the first 13 minutes?

Issue Solved.

That is 14 period . but on a 5 minute chart , there are 75 intraday candles, also i think there are 3 sessions in a day so using 25 also. If 75 period and 25 period both are in sync. Then i decide to trade.