Forum Discussion
Excel - how to show a negative time calculation
I am creating a time sheet that calculates the time used against a starting amount of hours purchased for consulting. I have used the "time" calculation to delete the time used. I have now got to where negative time has been used from the hours purchased. The help section tells me to switch to the "1904 data system" to allow the formula to show a negative number. I have gone to Excel File but do not see the "option" that is explained in help.
Any other suggestions.
For Example: The client has purchased 20 hours of consulting time.
In the desktop version of Excel for Windows:
Select File > Options.
Select Advanced in the navigation pane on the left.
Scroll down to the section 'When calculating this workbook'.
In Excel for Mac, the 1904 date system is the default setting.
- Great, thanks! However I'm really afraid of side effects, this is the kind of legacy option which is never tested...
A pity Microsoft does not fix the original issue, the format with brackets [h]:mm:ss;-[h]:mm:ss is supposed to work but this is bugged since forever. 😞If you don't use the 1904 date system, Excel cannot display negative times. Changing this would probably break other stuff, so it is very unlikely to happen.
I have been working on a spreadsheet, not huge...but when I changed to the 1904 system, it increased all my dates by 4 years....but now does show negative values in my time difference column
Yes, dates will change if you switch from the 1900 date system to the 1904 date system.
If you want to correct existing dates:
- Enter the number 1462 in an empty cell.
- Copy this cell.
- Select a range with dates that are 4 years off.
- Right-click in the selection.
- Select Paste Special... from the context menu.
- Select Subtract.
- Click OK.
