i'm an operator of netcafe, i usefor time records, like a1=time in b1=present time, cause i don't know when will the customer quit, i use formula c1=b1-a1, 2500/hour, everytime i multiply c1*2500, the result is error.. please help me, thanks
Not sure what you mean by 2500/hour?
Time is held as a fraction of a day, so 24 hours equals the number 1.
So if cell C1 shows this time:
and you want the minutes as a number, multiply C1 with 24 and 60:
and format the cell as a number or as General.