Syntax
ISBLANK(value)
| Parameter | Description |
|---|---|
| value | Parameter of the ISBLANK function. |
Examples
Check for missing data
Formula
=ISBLANK(A1)
Returns TRUE if A1 is completely empty. Returns FALSE if A1 contains 0, an empty string, a space, or any other value.
Conditional default
Formula
=IF(ISBLANK(B2), "N/A", B2)
Displays "N/A" when B2 is empty, otherwise shows B2's value. Common for reports where blanks should show a placeholder.
Count empty cells
Formula
=COUNTIF(A1:A100, "")
While not ISBLANK itself, this counts empty cells in a range. ISBLANK only works on single cells, so COUNTBLANK or COUNTIF is used for ranges.
Common Errors
#VALUE!
ISBLANK does not produce errors — it always returns TRUE or FALSE, even for error values in the cell (which return FALSE).
Tips
Empty string vs blank
A cell containing ="" (empty string formula) is NOT blank. ISBLANK returns FALSE. If you need to detect both, use A1="" which catches empty strings and blanks.
Use for data entry validation
=AND(NOT(ISBLANK(A1)), NOT(ISBLANK(B1))) checks that both required fields are filled in.
Conditional formatting
Use =ISBLANK(A1) as a conditional formatting rule to highlight empty cells in a data entry form — makes missing data immediately visible.
Try ISBLANK in Viztab
Import your data and use ISBLANK with 370+ other formulas. No signup required.
Open Viztab