Math & Trig

RADIANS Formula

RADIANS converts an angle from degrees to radians by multiplying by π/180. Since all spreadsheet trig functions (SIN, COS, TAN) require inputs in radians, RADIANS is the bridge between human-readable degree values and the radian input these functions need.

Syntax

RADIANS(angle)
ParameterDescription
angle Parameter of the RADIANS function.
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Examples

180 degrees to radians

Formula
=RADIANS(180)
Returns ~3.14159 (π). 180 degrees is exactly π radians.

Use with SIN

Formula
=SIN(RADIANS(30))
Returns 0.5. Converts 30° to radians first, then computes sine. This is cleaner than =SIN(30*PI()/180).

Right angle

Formula
=RADIANS(90)
Returns ~1.5708 (π/2). 90 degrees is π/2 radians.

Common Errors

#VALUE!

Non-numeric input returns #VALUE!. The argument must be a number.

Tips

Always use with trig functions

=SIN(30) is almost certainly wrong (30 radians ≈ 1,719°). You almost always want =SIN(RADIANS(30)) when working with degree values.

Manual conversion

RADIANS(x) = x × PI() / 180. The function is a convenience wrapper for this formula.

Common conversions

RADIANS(45)=π/4, RADIANS(90)=π/2, RADIANS(180)=π, RADIANS(360)=2π. These are the most-used conversions.

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