Frequency Converter

This page converts a frequency from one unit into another. Every value passes through the hertz, the SI unit frequency is held in, and frequency stays frequency: a unit only converts inside its own dimension.

How do you convert a frequency between hertz and rpm?

Pick the unit you have, pick the unit you want, and type the value. The page multiplies by the factor between the two and prints the arithmetic under the result, so the answer and the working are the same object.

1. Choose the unit your value is in. This page opens on the revolution per minute.
2. Choose the unit you want it in. This page opens on the hertz.
3. Type the value. The result and the factor behind it appear together.
4. Read the working. It converts into the hertz first and out again, which is the same two lines you would write by hand.

Frequency Conversion Table

One row per unit this page offers, each measured against the hertz. The last column says whether the factor is a definition or a reading of one.

Worked Examples

The question the bank ranked highest for this page, answered with the working.

Where These Factors Come From

Every number above is read from the knowledge base rather than computed for the page. These are the statements it holds for frequency.

• One hertz is one cycle per second, so the hertz is the reciprocal second. One revolution per minute is 1/60 Hz, which means 1 Hz is 60 rpm.
• An SI prefix multiplies a unit by a power of ten: k is 10^3, M is 10^6, G is 10^9, m is 10^-3, micro is 10^-6 and n is 10^-9. The prefix belongs to the unit, so 1 kV is 1000 V.
• How this page reports a result result in the target frequency unit; rpm is treated as cycles per minute

SI prefixes on this page

Is a Cycle the Same as a Revolution?

For a rotating shaft a cycle and a revolution are the same event counted the same way, which is why revolutions per minute carries the dimension of a frequency. The hertz counts cycles per second and rpm counts them per minute, so the two differ by the minute alone.

The rule behind this factor is the same for every unit - how SI prefixes scale a unit.

Frequently Asked Questions

Related Conversions

• Time sits in the same measurement group as frequency - convert a duration between seconds, minutes and hours.
• If you are measuring volumetric flow rate rather than frequency, the volumetric flow rate factors instead.
• If you are measuring power rather than frequency, energy delivered per second instead.
• If you are measuring pressure rather than frequency, the pressure factor table instead.
• If you are measuring mass rather than frequency, the mass factor table instead.
• If you are measuring energy rather than frequency, convert energy between joules and kilowatt-hours instead.

The rest of the family sits on the unit converter index.