Hertz to revolutions per minute (Hz to rpm) converter

What is a hertz to revolutions per minute converter?

A hertz to revolutions per minute converter is an online tool that translates a frequency expressed in hertz (Hz) into a rotational speed expressed in revolutions per minute (rpm), and vice versa. Both units describe how often something repeats, but they use different time bases: hertz counts cycles per second, while rpm counts full turns per minute. Because a single minute contains 60 seconds, the two scales are linked by a clean factor of 60, which makes the conversion fast and reliable.

This tool is useful any time you need to bridge the language of electrical engineering and physics, where frequency is stated in hertz, with the language of mechanics and motors, where rotational speed is almost always given in rpm.

How it works

The converter relies on the definition of each unit:

• Hertz (Hz) is the SI unit of frequency. One hertz equals one cycle, or one revolution, per second.
• Revolutions per minute (rpm) measures how many complete rotations occur in one minute.

Since one second holds 1/60 of a minute, one revolution per second is the same as 60 revolutions per minute. To go from hertz to rpm you multiply by 60; to go from rpm to hertz you divide by 60. The converter also accepts larger frequency prefixes such as kilohertz (kHz), megahertz (MHz), and gigahertz (GHz), scaling them to plain hertz before applying the factor of 60.

Formula

To convert hertz to revolutions per minute, multiply the frequency by 60:

$\text{rpm} = \text{Hz} \times 60$

To convert revolutions per minute back to hertz, divide by 60:

$\text{Hz} = \frac{\text{rpm}}{60}$

Hertz to revolutions per minute conversion table

The table below shows common hertz values and their equivalent rotational speeds in rpm:

Examples

Example 1: One hertz to rpm

A shaft spinning at exactly 1 Hz completes one full turn every second. Multiplying by 60 gives its speed in rpm:

$1 \text{ Hz} \times 60 = 60 \text{ rpm}$

Example 2: Revolutions per minute back to hertz

A small fan runs at 60 rpm. To express this as a frequency in hertz, divide by 60:

$\frac{60 \text{ rpm}}{60} = 1 \text{ Hz}$

Example 3: Mains frequency to motor speed

In many regions the electrical grid operates at 50 Hz. The synchronous speed of a simple two-pole motor matches that frequency, so converting it to rpm gives:

$50 \text{ Hz} \times 60 = 3000 \text{ rpm}$

Example 4: Kilohertz to rpm

A high-speed spindle drive is rated at 1 kHz, which is 1000 Hz. Converting the full kilohertz to rpm yields:

$1000 \text{ Hz} \times 60 = 60000 \text{ rpm}$

Notes

• The conversion factor is always 60, derived directly from the 60 seconds in a minute, so it never changes.
• When entering frequencies in kHz, MHz, or GHz, the converter first reduces them to hertz, which can lead to very large rpm figures.
• Rotational speed in rpm assumes one revolution equals one cycle; for systems with multiple poles or gear stages, the mechanical output speed may differ from this raw frequency-based figure.
• A zero frequency simply returns zero rpm, since a stationary object completes no cycles.

Frequently asked questions

How many rpm is 1 Hz?

One hertz equals 60 revolutions per minute, because one cycle per second repeated for the 60 seconds in a minute produces 60 cycles per minute.

How do I convert rpm to hertz?

Divide the rpm value by 60. For example, 60 rpm divided by 60 equals 1 Hz, and 3000 rpm divided by 60 equals 50 Hz.

Why is the conversion factor 60?

Hertz is measured per second and rpm is measured per minute. Since one minute contains 60 seconds, you multiply by 60 when going from hertz to rpm and divide by 60 when going the other way.

What is 50 Hz in rpm?

50 Hz equals 3000 rpm. This is why a two-pole electric motor connected to a 50 Hz supply has a synchronous speed of 3000 rpm.

Can I convert kilohertz or megahertz to rpm?

Yes. The converter scales kHz, MHz, and GHz down to plain hertz first, then multiplies by 60. For instance, 1 kHz equals 1000 Hz, which is 60000 rpm.

Are hertz and rpm interchangeable for any rotating system?

They are interchangeable as a measure of cycles or revolutions over time. However, whether a motor’s electrical frequency equals its mechanical rpm depends on the number of poles and any gearing, so check your equipment’s specifications for the actual shaft speed.