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Convert Radians per second to Hertz (rotational)

Instantly convert Radians per second (rad/s) to Hertz (rotational) (Hz) with our free online calculator.

Reviewed by Christopher FloiedUpdated

Formula: rad/s to Hzmultiply by 0.159155

Reference Table

Radians per second (rad/s)Hertz (rotational) (Hz)
10.159155
50.795775
101.59155
253.97887
507.95775
10015.9155

How to Convert Radians per second to Hertz (rotational)

Formula

To convert Radians per second (rad/s) to Hertz (rotational) (Hz): multiply by 0.159155

Step-by-Step

  1. Start with your value in Radians per second (rad/s).
  2. Multiply by 0.159155 to perform the conversion.
  3. The result is your value expressed in Hertz (rotational) (Hz).

Conversion Factor

1 rad/s = 0.159155 Hz

Reverse Factor

1 Hz = 6.28319 rad/s

Worked Example

Convert 25 Radians per second to Hertz (rotational): 25 rad/s = 3.97887 Hz

About Radian per second (rad/s)

The SI unit of angular velocity (ISO 80000-3 §3-7), equal to the rate of change of angular displacement in radians per second. rad/s is the native unit of every physics and engineering formula involving rotational motion: rotational power P = τ·ω (torque × angular velocity), angular momentum L = I·ω (moment of inertia × ω), rotational kinetic energy KE = ½·I·ω², centripetal acceleration a = ω²·r, and the time-derivative form of angular position θ(t) where ω = dθ/dt. Mechanical engineering (drivetrain dynamics, turbomachinery analysis per ASME PTC 6), robotics control loops (PID position-loop tuning in radians per second for joint actuators), gyroscope output (MEMS rate gyros report rad/s natively on the I²C/SPI register), and physics simulations (Bullet Physics, Newton Dynamics, PhysX) all work in rad/s. Reference values: Earth's rotation 7.27 × 10⁻⁵ rad/s (one full turn per 24 h ≈ 86,164 s sidereal day); a typical automotive crankshaft at 6,000 RPM = 628 rad/s; helicopter rotor 30-40 rad/s. 1 rad/s ≈ 9.5493 RPM.

About Hertz (rotational) (Hz)

Rotational frequency expressed in cycles per second — dimensionally identical to rev/s (1 Hz = 1 rev/s = 60 RPM = 2π rad/s) but more common in physics, vibration analysis, and rotor-dynamics contexts where the frequency-domain interpretation matters. Used in: rotor-dynamics critical-speed studies per API 684 and ISO 21940 (the first-bending-mode critical speed of a 200 MW steam turbine rotor is typically 25-35 Hz, well separated from the 50/60 Hz grid synchronous speed at 50/60 Hz exactly), NDT (Non-Destructive Testing) vibration surveys per ISO 10816, FFT spectral analysis of rotating-machinery vibration signatures (the 1× = running speed peak, 2× = misalignment, 3-10× = blade-pass or gear-mesh frequencies depending on machine type), and balancing-machine output per ISO 1940 / ISO 21940-11. NOT to be confused with Hz as an electrical / temporal / oscillatory frequency (though they share the same underlying '1/s' dimension and are sometimes deliberately conflated in spectral analysis).

Quick Facts

  • 1 Radian per second equals 0.159155 Hertz (rotational)
  • 1 Hertz (rotational) equals 6.28319 Radians per second
  • Radian per second is a unit of angular velocity
  • Hertz (rotational) is a unit of angular velocity
  • This conversion is commonly used in motor specifications, rotating machinery, and mechanical design
  • The Hertz (rotational) belongs to the metric system

Common Radian per second to Hertz (rotational) Conversions

Radians per second (rad/s)Hertz (rotational) (Hz)
0.010.00159155
0.10.0159155
0.250.0397887
0.50.0795775
10.159155
20.31831
30.477465
50.795775
101.59155
152.38732
203.1831
253.97887
507.95775
7511.9366
10015.9155
25039.7887
50079.5775
1000159.155
5000795.775
100001591.55

Understanding Radians per second

The Radian per second (symbol: rad/s) is a unit of angular velocity. The SI unit of angular velocity (ISO 80000-3 §3-7), equal to the rate of change of angular displacement in radians per second. rad/s is the native unit of every physics and engineering formula involving rotational motion: rotational power P = τ·ω (torque × angular velocity), angular momentum L = I·ω (moment of inertia × ω), rotational kinetic energy KE = ½·I·ω², centripetal acceleration a = ω²·r, and the time-derivative form of angular position θ(t) where ω = dθ/dt. Mechanical engineering (drivetrain dynamics, turbomachinery analysis per ASME PTC 6), robotics control loops (PID position-loop tuning in radians per second for joint actuators), gyroscope output (MEMS rate gyros report rad/s natively on the I²C/SPI register), and physics simulations (Bullet Physics, Newton Dynamics, PhysX) all work in rad/s. Reference values: Earth's rotation 7.27 × 10⁻⁵ rad/s (one full turn per 24 h ≈ 86,164 s sidereal day); a typical automotive crankshaft at 6,000 RPM = 628 rad/s; helicopter rotor 30-40 rad/s. 1 rad/s ≈ 9.5493 RPM.

Radians per second are commonly used in motor specifications, rotating machinery, and mechanical design.

Understanding Hertz (rotational)

The Hertz (rotational) (symbol: Hz) is a unit of angular velocity. Rotational frequency expressed in cycles per second — dimensionally identical to rev/s (1 Hz = 1 rev/s = 60 RPM = 2π rad/s) but more common in physics, vibration analysis, and rotor-dynamics contexts where the frequency-domain interpretation matters. Used in: rotor-dynamics critical-speed studies per API 684 and ISO 21940 (the first-bending-mode critical speed of a 200 MW steam turbine rotor is typically 25-35 Hz, well separated from the 50/60 Hz grid synchronous speed at 50/60 Hz exactly), NDT (Non-Destructive Testing) vibration surveys per ISO 10816, FFT spectral analysis of rotating-machinery vibration signatures (the 1× = running speed peak, 2× = misalignment, 3-10× = blade-pass or gear-mesh frequencies depending on machine type), and balancing-machine output per ISO 1940 / ISO 21940-11. NOT to be confused with Hz as an electrical / temporal / oscillatory frequency (though they share the same underlying '1/s' dimension and are sometimes deliberately conflated in spectral analysis).

It belongs to the metric measurement system.

Hertz (rotational) are commonly used in motor specifications, rotating machinery, and mechanical design.

Why Convert Radians per second to Hertz (rotational)?

Converting between Radians per second and Hertz (rotational) is a frequent requirement for engineers, scientists, and students working with angular velocity values. Different industries and regions favour different unit systems, so having a dependable conversion tool saves time and prevents errors in technical calculations. Whether you are verifying a specification sheet, cross-checking simulation results, or preparing a report for an international audience, accurate angular velocity conversion is essential.

Frequently Asked Questions

How do I convert Radians per second to Hertz (rotational)?

The SI unit of angular velocity (ISO 80000-3 §3-7), equal to the rate of change of angular displacement in radians per second. To convert Radians per second to Hertz (rotational), multiply by 0.159155. For example, 25 rad/s equals 3.97887 Hz.

How many Hertz (rotational) are in 1 Radian per second?

There are 0.159155 Hertz (rotational) in 1 Radian per second.

How many Radians per second are in 1 Hertz (rotational)?

There are 6.28319 Radians per second in 1 Hertz (rotational).

What is the formula for Radian per second to Hertz (rotational) conversion?

The formula is: multiply by 0.159155. This means 1 rad/s = 0.159155 Hz.

Is a Radian per second bigger than a Hertz (rotational)?

Yes. One Radian per second is larger than one Hertz (rotational) because 1 rad/s equals 0.159155 Hz, which is less than 1.

When do you need to convert between Radians per second and Hertz (rotational)?

Rotational frequency expressed in cycles per second — dimensionally identical to rev/s (1 Hz = 1 rev/s = 60 RPM = 2π rad/s) but more common in physics, vibration analysis, and rotor-dynamics contexts where the frequency-... Radian per second and Hertz (rotational) are both angular velocity units, so conversion comes up whenever one source of information uses one unit and another uses the other — a classic cross-reference challenge in engineering, trade, travel, and everyday life.

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