Error ExplainerExcel ##### in a cell (column too narrow)
A plain-words explanation of this Excel message: what it means, the usual causes, and the steps that fix it.
The message#####
Make the error yourself
Typed into Microsoft Excel 16.0 build 20326. This is the smallest example we could find that shows it.
| Cell | What was typed |
|---|---|
| A1 | 123456789 |
Column A was made 3 characters wide.
The cell looked at: A1.
Excel shows: ###
Why it happens
A row of hash signs is not a formula error. It means that the number, date or time does not fit in the column, so Excel shows hash signs instead of cutting the number (which could be misread). In the example the column is only about three characters wide for a nine-digit number. A second cause is a date or time that is negative, for example a date calculation with a result before 1900 or a time subtraction that gives less than zero; those can never be shown, however wide the column.
How to fix it
- Widen the column: double-click the line on the right side of the column letter, or choose Home > Format > AutoFit Column Width.
- Make the font smaller or change the number format to show fewer decimals.
- If widening does not help, check whether the value is a negative date or time. Subtract in the other order, or use
ABSor a text format.
The corrected version
| Cell | What was typed |
|---|---|
| A1 | 123456789 |
Column A was made 14 characters wide.
The cell looked at: A1.
Excel shows: 123456789
How to avoid it
Use AutoFit on columns with numbers, and avoid fixed narrow columns for amounts.
Questions
Why does the hash disappear when I click the cell?
The formula bar shows the real value. Only the cell display is too narrow.
This is an independent guide. It is not connected with Python, Microsoft, Google, GitHub or the Git project. Product names belong to their owners. Examples were run on 13 November 2026 in a practice folder or a blank workbook; your version may word a message slightly differently.