Radians to Turns (rad to turn)

1 radian equals 0.1591549431 turns (rounded).

1 radian = 0.1591549431 turns

How to convert radians to turns

To convert radians to turns, multiply the number of radians by 0.1591549431. The factor is rounded to 10 significant digits. To go the other way, multiply turns by 6.283185307 (rounded).

turns = radians × 0.1591549431

Example: 10 radians = 1.591549431 turns.

About these units

Radian (rad)

Metric (SI)Current unit

The SI unit of angle: the angle at the center of a circle subtended by an arc equal in length to the radius. A full turn is 2π radians (about 6.2832).

The radian builds its unit out of the circle itself. Lay a length of string equal to the radius along the circumference, and the angle that arc makes at the center is one radian. The SI Brochure calls it the coherent unit of plane angle, and it also serves as the coherent unit of phase angle, which grows by 2π radians over one period of a repeating wave. The same document notes that you could write rad as m/m, but warns that this is not intrinsic and can mislead, since angle is not the same kind of quantity as an ordinary ratio of lengths. It also records an alternative definition: a right angle equals π/2 radian.

A circle's circumference is 2π times its radius, so a full turn is 2π radians, about 6.2832, which makes one radian roughly 57.3 degrees, or about 0.159 of a turn. The SI Brochure's table of derived units expresses angular velocity in radians per second.

1 radian = 0.1591549431 turns (approximately).

Sources: BIPM SI Brochure, 9th edition (2019); Wikipedia: Angle; NIST Guide to the SI, Appendix B.8 (angle conversion factors)

Turn (turn)

General & non-SICurrent unit

One full revolution, 360 degrees or 2π radians.

A turn is the simplest angle to define: the whole way around, back to the starting direction. It also goes by cycle and revolution, and it equals 2π radians, 360 degrees, or 400 gradians. In the International System of Quantities, rotation is a plain count of revolutions, the angle divided by 2π radians, and it can be negative or exceed one.

Measuring in turns is older than it might seem. Percentage protractors marked in hundredths of a turn have existed since 1922, and in 1962 the astronomer Fred Hoyle proposed the terms centiturn, milliturn, and microturn. A 1974 German standard, DIN 1315, suggested the symbol pla, from the Latin for full angle. Some HP calculators, such as the HP Prime of 2013, accept tr as an angle unit. In CSS, 1turn equals 360deg, so a rule can rotate an element by 1.75turn. Binary angular measurement in computing also treats a full turn as the value 1, which lets integer overflow wrap an angle around for free.

The turn is the reference unit for angle on this site.

Sources: Wikipedia: Turn (angle); MDN Web Docs: CSS <angle>; NIST Guide to the SI, Appendix B.8 (angle conversion factors)

Related conversions

See all angle units.