Radians to Zodiac Signs (rad to sign)

1 radian equals 1.909859317 zodiac signs (rounded).

1 radian = 1.909859317 zodiac signs

How to convert radians to zodiac signs

To convert radians to zodiac signs, multiply the number of radians by 1.909859317. The factor is rounded to 10 significant digits. To go the other way, multiply zodiac signs by 0.5235987756 (rounded).

zodiac signs = radians × 1.909859317

Example: 10 radians = 19.09859317 zodiac signs.

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)

Zodiac Sign (sign)

AstronomicalTraditional unit (still used in some regions)

One twelfth of a turn (30 degrees): the arc of the ecliptic occupied by one sign of the zodiac.

The zodiac is a belt of sky about 8 degrees to either side of the ecliptic, the Sun's apparent yearly path, and it holds the Moon and the bright planets. It is divided into 12 equal signs of 30 degrees of ecliptic longitude each. Babylonian astronomers created the equal division in the late fifth century BCE, probably between 409 and 398 BCE, drawing on older star catalogs such as MUL.APIN. With the Sun advancing roughly a degree a day, it spends about a month in each sign.

Two systems exist. The tropical zodiac, used in Western astrology, anchors Aries to the Sun's position at the March equinox. The sidereal zodiac, used in Hindu astrology, ties the signs to the fixed stars. The signs are exact 30-degree slices, while the constellations they are named for vary widely in width, and precession of about 1.4 degrees per century has moved the March equinox from Aries into Pisces. A sign, as a unit, is therefore 1/12 of a turn rather than a constellation.

1 zodiac sign = 0.08333333333 turns (approximately).

Sources: Wikipedia: Zodiac; Wikipedia: Degree (angle)

Related conversions

See all angle units.