**Full name:** radian

**Plural form:** radians

**Symbol:** rad

**Alternate spelling:** c

**Category type:** angle

**Scale factor:** 1

The SI derived unit for angle is the radian.

Valid units must be of the **angle** type.

You can use this form to select from known units:

In mathematics and physics, the radian is a unit of angle measure. It is the SI derived unit of angle. It is defined as the angle subtended at the center of a circle by an arc of circumference equal in length to the radius of the circle. Angle measures in radians are often given without any explicit unit. When a unit is given, sometimes the abbreviation rad is used, sometimes the symbol c (for "circular").

radian to 1/6 circle

radian to 1/2 circle

radian to degree

radian to 1/16 circle

radian to arcsecond

radian to 1/4 circle

radian to grad

radian to percent

radian to full circle