Convert Time Elapsed into Minutes

[SiGill]

I have a table with a start time in it. I have a query that relates to the table. In my query I have a duration field Duration: Format(Now()-[Start Time],"hh:mm:ss") this gives me the length of time thats elapsed from the start time to now. I now need to convert that into Minutes elapsed. I searched this site and found this:

Mintues: TimeValue([Duration]*1440)

But I get Data Type mismatch in criteria expression. If I change it from Group By to Expression I get #Error as the result.

Could someone let me know where I am going wrong

 

[namliam]

TimeValue([Duration])*1440
or:
( Now()-[Start Time] ) * 1440
or:
( Now()-[Start Time] ) * 60 * 24

Note though that returns 6.5 for 6 min 30 secs...