I want to make a cell in my spreadsheet that updates a timestamp every time another cell is updated.

I have a SUMIF connected to a budget inflows/outflows tab in my spreadsheet and I want this cell to tell me the last time a particular figure is updated via a SUMIF calculation.

I have read that this functionality requires use of the Script Editor. I have used solutions posted by other users online but every solution either:

  • recalculates the timestamp cell every time ANY change is made to any part of the spreadsheet, and/or
  • recalculates the timestamp cell every time the spreadsheet is opened again

I need this cell to ONLY update the timestamp when the reference cell is either directly modified, or updated via another cell reference, like the SUMIF. It should not update upon opening the spreadsheet, or any changes made to any other part of the spreadsheet - only updates/edits to a particular, referenced cell.

If this has been asked in a similar form elsewhere, I apologise. I haven't found a solution that is specific to my needs; hopefully there is one.

Any assistance you can offer would be greatly appreciated.