ISOMITTED Function in Excel: Was an Optional Argument Left Out?

⏱ 1 min readUpdated 28 September 2026

LogicalLevel: ExpertAvailable in: Excel 365 / 2021+

In this article
  1. Syntax
  2. Examples
  3. Example 1
  4. Related functions

ISOMITTED is used inside LAMBDA to give optional parameters default values.

Syntax

=ISOMITTED(argument)
Argument What it means
argument A LAMBDA parameter.

Examples

Example 1

=LAMBDA(amt, [rate], amt * IF(ISOMITTED(rate), 18%, rate))

A GST function that uses 18% unless you pass another rate.

LAMBDA · LET

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