How to Use IFERROR and ISERROR in LibreOffice Calc

Handling formula errors is essential for creating clean, professional spreadsheets in LibreOffice Calc. This guide covers how to use the IFERROR and ISERROR functions to detect and manage errors like #DIV/0!, #N/A, and #VALUE!. You will learn the syntax, key differences, and practical examples for both functions to prevent broken formulas from cluttering your sheets.

The IFERROR Function

The IFERROR function evaluates an expression and returns a fallback value if the formula results in an error. If no error occurs, it returns the standard result of the formula.

Syntax

IFERROR(Value, Value_if_error)

Value: The formula or cell reference being evaluated.
Value_if_error: The custom result returned if an error is detected (such as text, a number, or an empty string "").

Example

If you are dividing cell A1 by cell B1, a standard division formula will return #DIV/0! if B1 is zero or blank:

=A1/B1

To display 0 instead of the error, use:

=IFERROR(A1/B1, 0)

To display a custom text message, wrap the string in quotation marks:

=IFERROR(A1/B1, "Division by Zero")

The ISERROR Function

The ISERROR function checks whether a specific value or formula produces any error. Unlike IFERROR, it only returns a boolean value: TRUE if there is an error, and FALSE if there is not.

Syntax

ISERROR(Value)

Value: The expression, formula, or cell reference you want to test.

Using ISERROR with the IF Function

Because ISERROR only outputs TRUE or FALSE, it is typically nested inside an IF statement to perform conditional actions.

=IF(ISERROR(A1/B1), "Error Occurred", A1/B1)

In this formula: 1. ISERROR(A1/B1) checks for an error. 2. If TRUE, the IF statement outputs "Error Occurred". 3. If FALSE, the IF statement calculates A1/B1.

Key Differences Between IFERROR and ISERROR

Feature	`IFERROR`	`ISERROR`
Output Type	Formula result or fallback value	Boolean (`TRUE` or `FALSE`)
Formula Length	Shorter; combines detection and replacement	Longer; requires pairing with `IF`
Efficiency	Evaluates the primary expression once	Evaluates the expression twice when nested with `IF`
Best Used For	Direct error replacement	Conditional formatting, logic checks, or complex branching

Practical Example: Trapping VLOOKUP Errors

A common scenario involves searching for records using VLOOKUP. When an item does not exist in the lookup range, Calc produces an #N/A error.

Using IFERROR:

=IFERROR(VLOOKUP(D2, A2:B10, 2, FALSE), "Not Found")

If the search key in D2 is not located within A2:B10, the formula cleanly outputs "Not Found" instead of #N/A.