Excel function reference

ISBLANK / ISNUMBER / ISTEXT / ISERROR / COUNTBLANK

Quick answer

A small toolkit for checking a cell rather than calculating with it: is it empty, is it the right type, did the formula above it fail?

ISBLANK(value) · ISNUMBER(value) · ISTEXT(value) · ISERROR(value) · COUNTBLANK(range)

Each IS-function returns a plain TRUE or FALSE, which makes them natural building blocks inside IF: "if this cell is blank, flag it" rather than a calculation in its own right. ISBLANK specifically tests for a genuinely empty cell, not a cell that merely displays as empty; a formula that returns an empty string "" still counts as not blank to ISBLANK, since the cell does hold something, it just happens to render as nothing. COUNTBLANK, unlike the IS-functions, works across a whole range at once and returns a count rather than a TRUE/FALSE per cell, and treats formula-produced empty strings the same way ISBLANK does: still not blank.

Syntax

ISBLANK(value) · ISNUMBER(value) · ISTEXT(value) · ISERROR(value) · COUNTBLANK(range)

Argument	Description
value	ISBLANK/ISNUMBER/ISTEXT/ISERROR: Required. Usually a cell reference: the thing being tested.
range	COUNTBLANK: Required. The cells to count empty cells across.

A real example: counting how many required fields are still missing

A short intake form with a few fields still unfilled:

=COUNTBLANK(A2:C2)

This counts every genuinely empty cell in the row in one step, which is the natural check before marking a submission as complete, rather than testing each field individually with ISBLANK.

Worked examples

Flagging a missing entry

	A
1	Submitted?
2

=ISBLANK(A2) → FALSE

Catching a lookup failure before it spreads

	A
1	Result
2	#N/A

=ISERROR(A2) → TRUE

(shown here as a stored text value for illustration, in a live sheet this would be a real error from the formula above)

Counting how many entries are still missing

	A	B	C
1	Field 1	Field 2	Field 3
2	Yes

=COUNTBLANK(A2:C2) → 2

Common mistakes

Using ISBLANK on a cell that holds a formula returning "" and expecting TRUE. That cell isn't actually blank to Excel, even though it looks empty; ISBLANK will return FALSE.
Wrapping ISERROR around a formula that's supposed to catch the error and recover from it. ISERROR only reports TRUE/FALSE; IFERROR is the one that substitutes a fallback value.
Running COUNTBLANK against a range that includes a formula returning "". Like ISBLANK, COUNTBLANK still counts that cell as not blank.

Related functions

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