Error ExplainerExcel #NULL! error
A plain-words explanation of this Excel message: what it means, the usual causes, and the steps that fix it.
The message#NULL!
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 | 1 |
| A2 | 2 |
| A3 | 3 |
| C1 | 4 |
| C2 | 5 |
| C3 | 6 |
| E1 | =SUM(A1:A3 C1:C3) |
The cell looked at: E1.
Excel shows: #NULL!
Why it happens
In a formula, a space between two ranges is an operator: it means "the cells that both ranges have in common" (the intersection). When the two ranges do not overlap, the result is empty and Excel shows #NULL!. In the example the space was typed where a comma belongs. It is nearly always a typing mistake: a space instead of a comma, or a missing colon in a range such as A1 A3.
How to fix it
- Look at the formula bar. Find a space between two ranges.
- Replace it with a comma if you want both ranges (
SUM(A1:A3,C1:C3)), or with a colon if you want one range (A1:C3). - If your computer uses semicolons as list separators, use a semicolon instead of the comma.
The corrected version
| Cell | What was typed |
|---|---|
| A1 | 1 |
| A2 | 2 |
| A3 | 3 |
| C1 | 4 |
| C2 | 5 |
| C3 | 6 |
| E1 | =SUM(A1:A3,C1:C3) |
The cell looked at: E1.
Excel shows: 21
How to avoid it
Do not type spaces inside references. Click the cells with the mouse so that Excel writes the separators for you.
Questions
Is the intersection operator ever useful?
Yes, with named ranges: =Sales Q1 returns the cell where the named row and column cross.
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.