IMTAN Function in Excel: Tangent of a Complex Number

IMTAN Function in Excel: Tangent of a Complex Number 1
⏱ 1 min readUpdated 5 October 2026

Complex numbersLevel: ExpertAvailable in: Excel 2013+

In this article
  1. Syntax
  2. Examples
  3. Example 1
  4. IMTAN in practice
  5. Where you will use it
  6. Worked example
  7. Mistakes people make
  8. Related functions

IMTAN returns tan(z). Complex numbers are text like 3+4i; build them with COMPLEX.

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Syntax

=IMTAN(inumber)
Argument What it means
inumber Complex number as text, e.g. “3+4i”

Examples

Example 1

=IMTAN(A2)

Result: -0.000187346204629478+0.999355987381473i. See the worked example table below for more cases.

IMTAN in practice

Where you will use it

  • AC circuit calculations (impedance, phase)
  • Signal processing
  • Engineering coursework

Worked example

zFormulaResult
3+4i=IMTAN(A2)-0.000187346204629478+0.999355987381473i
1-i=IMTAN(A3)0.271752585319512-1.08392332733869i
2i=IMTAN(A4)0.964027580075817i

Results calculated in Excel.

Mistakes people make

MistakeWhat to do instead
Spaces inside the text"3 + 4i" gives #NUM!; write 3+4i
Result is textUse IMREAL/IMAGINARY to get numbers back

COMPLEX · IMABS · IMREAL

📚 Part of the free Excel course: Beginner → Expert · Try it in the Formula Lab or ask the AI Helper.

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