Why does ISBLANK return FALSE for a cell that looks empty?
Formula (Excel and Google Sheets)
=IF(LEN(TRIM(B2))=0,"Empty","Has data")The cell holds a formula returning "" or a space. Test what it shows instead: =IF(LEN(TRIM(B2))=0,"Empty","Has data").
- Result on the example
- one result per row in
C2, filled down toC6 - Works in
- Every current version
- Google Sheets
- Same formula
See it work
The formula is already in C2, filled down to C6. Change any input and the result updates, or edit the formula to experiment.
How it works
ISBLANK is TRUE only for a cell with nothing in it at all: no value and no formula. A formula that returns "" and a cell with a space look empty but aren't, so ISBLANK says FALSE. LEN(TRIM(B2))=0 checks what the cell shows: after removing spaces, is anything left?
=IF(LEN(TRIM(B2))=0,"Empty","Has data")Result"Empty"
B2(empty)The value in B2.
TRIM(B2)""TRIM: Removes extra spaces, leaving single spaces between words.- text
B2(empty)
- text
LEN(TRIM(B2))0LEN: Number of characters.- text
TRIM(B2)""
- text
LEN(TRIM(B2))=0TRUEThe = operator tests whether the two sides are equal.
IF(LEN(TRIM(B2))=0,"Empty","Has data")"Empty"IF: Returns one value if a test is true, another if false.- logical_test
LEN(TRIM(B2))=0TRUE - value_if_true
"Empty" - value_if_false
"Has data"not used
- logical_test
In Google Sheets
The same formula works in Google Sheets: =IF(LEN(TRIM(B2))=0,"Empty","Has data"). We ran it in Google Sheets mode on the same data and it returns the same results.
Other ways to do it
Each one was run on the same example sheet.
| Formula | Result | When to use it |
|---|---|---|
| =IF(B2="","Empty","Has data") | Empty, Empty, Has data…Different result | ="" treats an empty cell and a formula returning "" as empty, but not a space. The single-space cell shows "Has data". |
| =IF(ISBLANK(B2),"Empty","Has data") | Empty, Has data, Has data…Different result | ISBLANK is TRUE only for a cell with nothing in it. The "" formula and the space both show "Has data". |
Common mistakes
- A 0 isn't empty, even when a number format hides it.
- Text pasted from web pages can contain non-breaking spaces that TRIM leaves behind. Remove them with
SUBSTITUTE(B2,CHAR(160),"").
Try it yourself
Same data, empty answer cell. Your formula is graded instantly, then re-checked on changed data, so a typed-in number won't pass.
Why does ISBLANK return FALSE for a cell that looks empty
C2, show "Empty" when B2 shows nothing, whether it is truly empty, a formula returning "" or just spaces, otherwise "Has data". Fill down to C6.Questions
Can a formula return a truly empty cell?
No. A formula always returns something; return "" and test with ="" or LEN.
Does Google Sheets behave the same?
Yes: ISBLANK is FALSE there too for a formula that returns "".
Checked by running on 2026-10-30: every formula and result on this page was calculated by the Spreadsheet Practice formula engine, in both Excel and Google Sheets modes.