Angular Velocity Calculator

Calculate rotational speed from angular displacement, linear speed, frequency, or period.

Rotational Motion Calculator
Choose a known relationship and enter the measured quantities.

About Angular Velocity

Angular velocity measures how quickly an object rotates and indicates the rate at which its angular position changes. Its standard SI unit is radians per second. Unlike linear velocity, which describes distance traveled along a path each second, angular velocity applies to every point on a rigid rotating body. Points farther from the axis move faster in linear terms, but all points complete the same angle during the same interval. Several equivalent relationships can determine angular velocity. Dividing angular displacement in radians by elapsed time gives average angular velocity. When linear tangential speed and radius are known, angular velocity equals speed divided by radius. A periodic rotation with frequency f has angular velocity equal to 2 pi times f, while a known period T gives 2 pi divided by T. This calculator exposes all four methods and converts the final result to revolutions per minute for practical comparison. Angles entered in the displacement method are converted from degrees to radians before division. One complete revolution is 360 degrees or 2 pi radians. As a result, an object completing one turn every two seconds rotates at pi radians per second and 30 revolutions per minute. Frequency in hertz counts complete cycles each second, so one hertz corresponds to 2 pi radians per second and 60 rpm. These conversions are exact apart from displayed rounding. Angular velocity is a vector in formal mechanics. Its magnitude is the angular speed shown here, while its direction lies along the rotation axis according to the right-hand rule. A negative sign can encode opposite rotation, but this calculator accepts positive magnitudes for straightforward speed calculations. If speed changes over time, the result from displacement and time is an average rather than an instantaneous value. Applications include motors, wheels, turbines, gears, laboratory centrifuges, orbital motion, and rotating machinery. Use measurements expressed in the units shown beside each field and select the relationship matching the quantities you actually know. Real mechanisms may include slip, changing radius, gear ratios, or acceleration, so ensure the selected inputs refer to the same rotating member and time interval. For safety-critical equipment, confirm rotational limits using calibrated sensors and manufacturer data rather than relying only on a theoretical conversion.

Angular Velocity Examples

Common rotational motions expressed in radians per second and rpm.

Known ValuesAngular VelocityContext
360 degrees in 2 seconds3.141593 rad/s, 30 rpmOne turn in two seconds
Linear speed 10 m/s, radius 2 m5 rad/s, 47.746 rpmPoint on a wheel
Frequency 50 Hz314.159265 rad/s, 3000 rpmSynchronous rotation rate

How to Calculate Angular Velocity

  1. Choose the method matching your known rotational measurements.
  2. Enter positive values using the units displayed beside each field.
  3. Calculate angular velocity and read both radians per second and rpm.
  4. Check that all measurements describe the same axis and time interval.

Angular Velocity FAQ

What is the SI unit of angular velocity?

The SI unit is radians per second, written rad/s. Radians are dimensionless mathematically, but the label clarifies that the quantity is angular.

How do I convert angular velocity to rpm?

Multiply radians per second by 60 and divide by 2 pi. The calculator performs this conversion automatically.

Is angular velocity the same at every point on a wheel?

Every point on a rigid wheel shares the same angular velocity. Linear tangential velocity increases with distance from the axis.

Can angular velocity be negative?

Yes, a sign can identify direction relative to a chosen axis. This calculator reports positive speed magnitudes for common conversion tasks.

What is the difference between frequency and angular velocity?

Frequency counts complete cycles per second, while angular velocity measures radians swept per second. Multiplying frequency by 2 pi converts hertz to radians per second.