Round time to nearest 15min interval in Excel

Question

I\'ve an excel spreadsheet with a column which has the date and time of a particular event. I would like to round this to the nearest 15 minute interval so that I can count

Answer 1

Simpler ??

=B2-MOD(B2,15/24/60)

Knowing that for Excel 1 day = 24 hrs = 1,
15/24/60 (= 0.0104166666666667) is the numeric equivalent equivalent of 15 min.