One way:

A1: <start date-time
B1: <end date-time

Split Date & time (format as date or time as appropriate):

C1: =INT(A1)
D1: =MOD(A1,1)

Difference:

G: =B1-A1

Format this last using Format/Cells/Number/Custom [h]:mm:ss. The
brackets prevent roll-over at 24 hours.


In article ,
Kajuliano wrote:

Hi--

I'm new to excel and here is my issue:

I have two columns of data, the first column has both the date
(year-month-date) and time (in hours, minutes, and seconds-military) that a
participant started my questionnaire. The second column has the same exact
information (both date and time) but this tells me when the participant ended
the survey. This information lets me know how long it took an indiviudual to
complete the questionnaire and on what day they started it.

I need to:

1. split the date and time into two different columns (for both column 1 and
2- giving me 4 columns total, 2 with date, 2 with time)
2. calculate the time it took the participant to complete the survey
(subtract the end time from the start time)

I really have no idea where to begin, so any help would be appreciated-
thanks!