Hi,
column A is time format, column B is date format, column C is duration in decimal hours of that pair from the row above.

A B C
1 12:45:00 14-Jan-2017
2 00:30:00 16-Jan-2017 35.75

what formula to use in C to get the duration as decimal hours please ?

I see in another thread =MOD(A63-A62,1)*24 to crossover a day but poster hadnt a date column , I have more than 1 day gaps !

DBenz

=(A2-A1)*24 works for me.

Try
= ((B2+A2)-(B1+A1))*24

@NoSparks

You are right. I misread it to have both time and date in one cell.

Hi,
created the cells with time format A and date format B and general C and got #value! so made C number format 2 dec places still get #value!

ah solved it, I had done a test lower down and of course the row numbers are not 1 and 1, silly me !

DBenz

That tells me the time/date may not actually be numbers.

You can verify this by using ISNUMBER

Try...

=ISNUMBER(A1)

Do you get false or true? Try this also with what's in B1.

If you get false, you may have a time/date which looks like a number, but in reality is text. You need to convert to text or check to see if you have any extra spaces.