##### Hash Marks in Excel
Excel shows ##### when a value does not fit the column width, or when a negative date/time is shown with a date format.
Widen the column
- Double-click the boundary between column headers (auto-fit)
- Or Home → Format → AutoFit Column Width
Change number/date format
Use a shorter format or General so the value fits.
Negative date/time
Some date formats cannot show negative values → #####. Fix the calculation or use a plain number format.
##### is a display issue, not a formula error like #VALUE!. The formula may already be correct.