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RADIANS Function

Excel 2007+

Summary

The RADIANS function converts angle measurements from degrees to radians, essential for trigonometric calculations in Excel that require radian inputs.

Syntax

RADIANS(angle)

Parameters

Parameter	Type	Required	Description
angle	`Number`	Yes	The angle measurement in degrees that you want to convert to radians

Using the RADIANS Function

Use RADIANS when your angle data is in degrees but Excel's trigonometric functions (SIN, COS, TAN, etc.) require radians. This conversion ensures accurate calculations for geometry, physics, and engineering applications.

Common RADIANS Examples

Convert 270 Degrees to Radians

=RADIANS(270)

Converts 270° (three-quarters of a circle) to radians, returning approximately 4.712389 (equivalent to 3π/2).

Convert 45 Degrees for Trigonometry

=SIN(RADIANS(45))

Calculates sine of 45° by first converting to radians, returning approximately 0.7071.

Convert Cell Value

=RADIANS(A1)

Converts the degree value in cell A1 to radians for further calculations.

Frequently Asked Questions

Excel's trigonometric functions expect angles in radians, not degrees. RADIANS converts your degree measurements for accurate results.

RADIANS handles negative degrees correctly, converting them to negative radians.

Use the DEGREES function to convert radians back to degrees.

Common Errors and Solutions

#VALUE!

Cause: Angle argument is not numeric

Solution: Ensure the angle input is a number or numeric cell reference

Incorrect trig results

Cause: Forgetting to use RADIANS with degree angles

Solution: Always wrap degree values: SIN(RADIANS(A1))

Notes

1 radian ≈ 57.3 degrees
π radians = 180 degrees
RADIANS(180) returns π (3.14159...)
Use with SIN, COS, TAN, ASIN, ACOS, ATAN functions

Compatibility

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

Not available in:

Content last reviewed: December 9, 2025
Update frequency: As needed
Excel versions tested: Excel 2007+