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Frequency Converter

Convert frequency between hertz and its multiples (mHz to THz), rotational speeds (revolutions per minute, degrees per second) and angular frequency in radians per second. Each result comes with the period of one cycle, T = 1 ÷ f, so you can move between how often something repeats and how long one repetition lasts.

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Convert a Frequency

Frequency cannot be negative here, so negative values are rejected. The page also shows the period, T = 1 ÷ f.

Decimals and scientific notation such as 1.5e3 are accepted.
Automatic shows exact results in full and rounds long ones to 12 significant digits. A value too small for the chosen decimal places is shown with 3 significant digits instead of 0.

How to Use the Frequency

  1. Type the value you want to convert in Value to convert.
  2. Pick the starting frequency unit in From unit and the one you want in To unit. The lists are grouped by measurement system.
  3. Read the result and the formula directly under the form; it updates as you type. Use Swap units to reverse the direction. The period of one cycle is shown below the result.
  4. Scroll to the table to see the same value in every available unit, change Precision if you need fewer digits, or press Copy result.

About This Tool

Electronics hobbyists and radio engineers, audio and music students, people reading motor and fan speeds in RPM, mechanical engineers using angular velocity, and anyone comparing CPU or Wi-Fi clock speeds.

Input: A number and a unit  ·  Output: The same frequency in every unit.

Features and Limitations

Features

  • SI hertz from millihertz to terahertz, plus RPM, rad/s, °/s, cycles per hour and per day.
  • Shows the period T = 1 ÷ f in seconds, milliseconds, microseconds, nanoseconds or picoseconds as appropriate.
  • Exact except for π, which is taken to 45 digits when converting radians (1 rad/s = 1/(2π) Hz).
  • Equivalence line and a table with every unit.

Limitations

  • rad/s is angular frequency ω = 2πf, not cycles per second. Mixing it up with Hz is a factor-of-6.28 error; the converter does this conversion for you.
  • Frequencies of zero have no period, so no period is shown for 0 and negative values are rejected.
  • Results are computed in your browser; nothing you enter is sent to a server.

Example

2.4 GHz = 2 400 000 000 Hz, with a period of about 0.417 ns. 3000 RPM = 50 Hz. 60 Hz = 3600 RPM. 440 Hz = 0.44 kHz. 1 Hz = 6.283185 rad/s. 1 rad/s = 9.549297 RPM.

Frequently Asked Questions

How do I convert RPM to Hz?

Divide by 60. 3000 RPM is 50 revolutions per second, 50 Hz. To go from Hz to RPM, multiply by 60: a 60 Hz mains supply corresponds to 3600 RPM for a two-pole motor.

What is the difference between Hz and rad/s?

Hertz counts complete cycles per second. Radians per second measures angle: one full cycle is 2π radians, so ω (rad/s) = 2π × f (Hz). 1 Hz is 6.2832 rad/s.

How do I find the period from a frequency?

Take the reciprocal: T = 1 ÷ f. A 1 kHz tone has a period of 1 ms; a 2.4 GHz Wi-Fi signal has a period of about 0.417 ns (417 ps). The page shows this for the value you enter.

Why is a negative frequency rejected?

A physical frequency is a count of repetitions per unit time and so cannot be negative. (Signal processing sometimes uses negative frequencies for phase direction; that is outside this tool.)

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