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COS Function

Excel 2007+

Summary

The Excel COS function calculates the cosine of a specified angle provided in radians. This trigonometric function is essential for mathematical calculations, geometric analysis, and scientific computations within spreadsheets.

Syntax

COS(number)

Parameters

Parameter	Type	Required	Description
number	`Number`	Yes	Angle value in radians (required argument)

Using the COS Function

COS is a core trigonometric function used to determine the cosine value of angles in radians. It's commonly applied in physics calculations, wave analysis, geometric modeling, and any scenario requiring trigonometric relationships. Convert degrees to radians using RADIANS() or PI()/180 multiplication.

Common COS Examples

Cosine of Specific Radian Value

=COS(1.047)

Calculates cosine of 1.047 radians, approximately 60 degrees. Result: 0.5001711

Convert Degrees to Radians with PI()

=COS(60*PI()/180)

Cosine of 60 degrees using degree-to-radian conversion. Result: 0.5

Using RADIANS Function

=COS(RADIANS(60))

Cosine of 60 degrees using the RADIANS helper function. Result: 0.5

Frequently Asked Questions

COS requires angles in radians. Use RADIANS(degrees) or degrees*PI()/180 for conversion.

COS returns values between -1 and 1, representing the full range of cosine ratios.

Yes, COS supports negative angles and returns appropriate cosine values.

Common Errors and Solutions

#VALUE! error

Cause: Non-numeric angle provided

Solution: Ensure the number argument contains valid numeric data

Unexpected results

Cause: Angle provided in degrees instead of radians

Solution: Convert degrees using RADIANS() or PI()/180

Notes

Cosine values always range from -1 to 1
To convert degrees: multiply by PI()/180
π radians = 180 degrees
Combine with SIN for polar-to-rectangular conversions
Available across all Excel versions

Compatibility

Available in: Excel 2007, Excel 2010, Excel 2013, Excel 2016, Excel 2019, Excel 2021, Microsoft 365

Not available in:

Content last reviewed: December 11, 2025
Update frequency: As needed
Excel versions tested: Excel 2007+