Engineering

IMARGUMENT Function in Excel

Returns the argument theta, an angle expressed in radians.

Syntax

  • =IMARGUMENT(inumber)

Arguments

  • inumber (required): Complex number

Examples

  • =IMARGUMENT("3+4i") - Argument of 3+4i - Result: 0.927

IMARGUMENT in technical sheets

  • Document units in adjacent cells — many engineering functions require exact unit strings.
  • Use [CONVERT](/functions/convert/) for unit changes before specialized formulas.
  • Validate inputs with [ISNUMBER](/functions/isnumber/) and range checks.

Common errors

  • #NUM! if not valid complex number

Use cases

  • Complex analysis
  • Phase calculation
  • Signal processing

Frequently asked questions

  • What is the IMARGUMENT function in Excel? IMARGUMENT returns the argument theta, an angle expressed in radians. The syntax is =IMARGUMENT(inumber). Typical use cases include complex analysis, phase calculation, signal processing.
  • How do I use the IMARGUMENT function? To use IMARGUMENT, type =IMARGUMENT( in a cell and provide the required arguments. Excel will show you the syntax and parameter hints as you type. Make sure to close the parentheses and press Enter to execute the function.
  • Why is IMARGUMENT not working in my Excel? Common issues with IMARGUMENT include #NUM! if not valid complex number. Start by checking the syntax =IMARGUMENT(inumber), then verify each referenced cell or range.

Editorial review

  • Reviewed by Excel.Directory Editorial Team. Updated May 2026.