Excel ISNUMBER Function

ISNUMBER returns TRUE when a value is numeric and FALSE when it is not.

Use it to validate inputs, detect numeric lookup results, check whether text-search formulas found a match, or branch logic based on whether a cell contains a number.

Choose a value Use a cell, constant, or formula

Test the value type Excel checks for numeric data

Return TRUE or FALSE The result can drive other logic

ISNUMBER syntax & arguments

Syntax

=ISNUMBER(value)

Required Optional

1

value
Required

The value, cell reference, or formula result to test.

Example

=ISNUMBER(A2)

Return TRUE when A2 contains a numeric value, date, or time, and FALSE otherwise.

ISNUMBER caveats

ISNUMBER checks the actual value type, not just whether something looks numeric on screen.

Numbers stored as text return FALSE

A value that looks like 123 may still be text, which means ISNUMBER returns FALSE.
Dates and times return TRUE

Excel stores valid dates and times as numbers, so ISNUMBER treats them as numeric values.
Errors return FALSE

If value is an error, ISNUMBER returns FALSE instead of passing the error through.
It can test whether text was found

Use =ISNUMBER(FIND("ID", A2)) to check whether A2 contains ID. FIND returns a position number when ID is found, so ISNUMBER returns TRUE. If ID is missing, FIND returns #VALUE! and ISNUMBER returns FALSE.