SEC Function in Excel: Secant

SEC Function in Excel: Secant 1
⏱ 1 min readUpdated 5 October 2026

Maths & trigLevel: ExpertAvailable in: Excel 2013+

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

SEC returns 1/COS(x).

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Syntax

=SEC(number)
Argument What it means
number Value (angles in radians)

Examples

Example 1

=ROUND(SEC(A2),5)

Result: 1. See the worked example table below for more cases.

SEC in practice

Where you will use it

  • Engineering and physics formulas
  • Geometry and surveying
  • Coursework

Worked example

xFormulaResult
0=ROUND(SEC(A2),5)1
1.047197551=ROUND(SEC(A3),5)2
1=ROUND(SEC(A4),5)1.85082

Results calculated in Excel.

Mistakes people make

MistakeWhat to do instead
Degrees instead of radiansWrap in RADIANS for angles
Out-of-range input#NUM! or #DIV/0!

SIN · COS · TAN

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Keep reading

Excel Functions A–ZPROB Function in Excel: Probability From a TableExcel Functions A–ZFINV Function in Excel: F Critical Value (Older Name)Excel Functions A–ZACOS Function in Excel: Angle From a Cosine
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