Math & Trig

COT Function in Excel

Returns the cotangent of an angle in radians.

Syntax

  • =COT(number)

Arguments

  • number (required): Angle in radians

Examples

  • =COT(PI()/4) - Cotangent of 45 degrees - Result: 1

COT in reporting workflows

  • Use absolute references when copying formulas across rows.
  • For conditional totals see [SUMIF](/functions/sumif/) and [SUMIFS](/functions/sumifs/).
  • Filtered lists may need [SUBTOTAL](/functions/subtotal/) instead of SUM on visible cells only.

Common errors

  • #DIV/0! when angle is multiple of PI

Use cases

  • Trigonometry
  • Engineering
  • Physics

Frequently asked questions

  • What is the COT function in Excel? COT returns the cotangent of an angle in radians. The syntax is =COT(number). Typical use cases include trigonometry, engineering, physics.
  • How do I use the COT function? To use COT, type =COT( 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.
  • What happens if COT encounters errors? If COT encounters invalid arguments or calculation errors, it may return error values like #VALUE!, #NUM!, or #DIV/0!. Check your input values and ensure they meet the function's requirements.
  • Why is COT not working in my Excel? Common issues with COT include #DIV/0! when angle is multiple of PI. Start by checking the syntax =COT(number), then verify each referenced cell or range.

Editorial review

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