Question re: cell date / time calculation (e.g. =now, =today)

[Jeffy]

Is there a way to update cell A1 with the date and/or time any data has changed in a single tab?

So if I go into a tab in a file with multiple tabs and change any cell's data (besides A1) from x to y, then I want cell A1 to automatically calculate the date/time I changed my data.

Thanks in advance

[FDibbins]

the =DATE() (which just puts in the current date) and =NOW() (which puts in the current date AND time) are both volatile functions...meaning they will change any time anything in the workbook changes.

So, =TODAY() will show today's date until tomorrow, then will change to tomorrow if any change is made to the WB
Likewise =NOW() will show date/time, and the TIME part will update with any WB change.

The only way I know of to be able to see when/how long ago a change was made to a WB is through VBA