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Frequency Converter

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About This Tool

Frequency Converter: Convert Between All Frequency Units

The Frequency Converter is a free online tool that instantly converts frequency values between 13 units spanning SI, rotational, audio, angular, and time-based measurement systems. Whether you need to convert a radio signal from megahertz to gigahertz, translate a motor speed from RPM to hertz, or compare a musical tempo in BPM to its equivalent in radians per second, this tool delivers high-precision results in real time with configurable decimal places.

All conversions are performed client-side using Hertz (Hz) as the normalized base unit. Enter a value in any supported unit and every other unit updates simultaneously. Enable the "Show all unit conversions" option to display a grouped reference table across all three unit categories, making it easy to compare values side by side for electronics, signal processing, music production, and mechanical engineering applications.

Supported Frequency Units

The converter covers 13 units grouped into three practical categories.

SI Units

  • Hertz (Hz) — The SI unit of frequency, defined as one cycle per second. Named after Heinrich Hertz, it is the universal standard for measuring frequency in science and engineering. The pitch of middle C on a piano is approximately 261.6 Hz, and standard AC mains power in many countries operates at 50 or 60 Hz.
  • Kilohertz (kHz) — Equal to 1,000 Hz. Commonly used for audio frequencies, AM radio broadcasting (530-1700 kHz), and ultrasonic applications. The upper limit of human hearing is approximately 20 kHz.
  • Megahertz (MHz) — Equal to 1,000,000 Hz. Used for FM radio (87.5-108 MHz), television broadcasting, older computer processor speeds, and some wireless communication standards.
  • Gigahertz (GHz) — Equal to 1,000,000,000 Hz. The standard unit for modern CPU clock speeds, WiFi frequencies (2.4 GHz and 5 GHz bands), mobile phone networks, and microwave communication systems.
  • Terahertz (THz) — Equal to 1,000,000,000,000 Hz. Used in spectroscopy, security imaging, and emerging high-bandwidth wireless research. Terahertz radiation fills the gap between microwave and infrared in the electromagnetic spectrum.

Rotational and Audio Units

  • Revolutions per minute (RPM) — The number of complete rotations in one minute. One of the most common mechanical engineering units, used for motor speeds, engine tachometers, hard drive spindle speeds, and centrifuge settings. A typical car engine idles at 600-1000 RPM, while a computer hard drive spins at 5400-7200 RPM. Since 1 RPM = 1/60 Hz, converting RPM to Hz involves dividing by 60.
  • Revolutions per second (RPS) — Complete rotations per second, numerically equivalent to Hertz for rotational motion. Used in scientific contexts where per-second units are preferred. A standard washing machine spin cycle operates at approximately 15-20 RPS (900-1200 RPM).
  • Beats per minute (BPM) — The standard tempo measurement in music. Numerically equivalent to RPM in conversion (1 BPM = 1/60 Hz), but used exclusively in musical and exercise contexts. A resting heart rate is typically 60-100 BPM, and dance music typically ranges from 120-140 BPM.

Time-Based and Angular Units

  • Cycles per minute (cpm) — Identical in magnitude to RPM and BPM (1/60 Hz per unit), but used in mechanical oscillation and process engineering contexts where "cycle" better describes the motion than "revolution" or "beat."
  • Cycles per hour (cph) — One cycle per hour equals 1/3600 Hz. Used for very slow periodic processes such as tidal cycles, geological oscillations, and some industrial batch processes.
  • Radians per second (rad/s) — The angular frequency unit, related to Hertz by the factor 2π. One Hertz equals approximately 6.2832 rad/s. Angular frequency is fundamental in physics, control systems, and signal processing because it simplifies equations involving sinusoidal functions.
  • Frames per second (FPS) — The display refresh rate unit, numerically equivalent to Hertz. Standard video runs at 24-30 FPS, modern gaming targets 60-144 FPS, and high-speed cameras can capture thousands of FPS for slow-motion analysis.
  • Degrees per second (°/s) — Angular velocity measured in degrees rather than radians. Since a full rotation is 360°, one Hz equals 360°/s. Used in navigation, robotics, and gyroscope specifications where degree-based angular measurements are more intuitive.

How Frequency Conversion Works

Every conversion is normalized through Hertz in two steps. First, the input value is multiplied by the conversion factor of the source unit to obtain the equivalent frequency in Hertz. Then that Hertz value is divided by the conversion factor of the target unit to produce the final result. This two-step approach ensures consistent accuracy for any pair of units without requiring a dedicated formula for every possible combination.

As an example, converting 3000 RPM to radians per second:

  • 3000 RPM × (1/60) Hz per RPM = 50 Hz
  • 50 Hz ÷ (1/2π) Hz per rad/s = 50 × 2π = 314.16 rad/s

This confirms that a motor spinning at 3000 RPM has an angular frequency of approximately 314.16 radians per second, a relationship frequently used in electrical motor analysis and control system design.

Key Frequency Reference Values

  • AC mains (50 Hz): 50 Hz = 3000 RPM = 314.16 rad/s
  • AC mains (60 Hz): 60 Hz = 3600 RPM = 376.99 rad/s
  • Musical A4 tuning: 440 Hz = 26,400 RPM = 2764.6 rad/s
  • WiFi 2.4 GHz: 2,400,000,000 Hz = 2400 MHz = 2.4 GHz
  • Human hearing range: 20 Hz to 20,000 Hz (20 kHz)
  • Typical heart rate: 60-100 BPM = 1-1.67 Hz

Practical Applications of Frequency Conversion

Frequency measurement spans an enormous range from sub-hertz geological phenomena to terahertz electromagnetic waves. Here are common scenarios where unit conversion is essential:

  • Electronics and Signal Processing: Engineers routinely convert between Hz, kHz, MHz, and GHz when designing filters, oscillators, and communication circuits. A low-pass filter specification might be given in kHz while the system clock is in MHz, requiring accurate conversion for correct component selection.
  • Mechanical Engineering: Motor and turbine speeds are typically specified in RPM, but dynamic analysis and vibration calculations require conversion to Hz or rad/s. A motor rated at 1750 RPM needs to be expressed as 29.17 Hz or 183.26 rad/s for frequency-domain vibration analysis.
  • Music Production: Musicians work in BPM for tempo, but audio engineers need Hz for pitch and frequency analysis. Converting a 120 BPM tempo to 2 Hz helps in designing beat-synchronized effects and understanding the fundamental rhythm frequency.
  • Physics and Control Systems: Angular frequency (rad/s) is the natural unit for many physics equations, but laboratory instruments typically display results in Hz. Converting between these units is routine in experimental physics, control system design, and signal analysis.
  • Video and Display Technology: Display refresh rates are specified in Hz (or equivalently FPS), while content frame rates use FPS notation. A 144 Hz gaming monitor refreshes at 144 FPS, and understanding this equivalence is important for matching content frame rates to display capabilities.

Tips for Using the Frequency Converter

  • Enable "Show all unit conversions" to display every supported unit simultaneously, grouped by category. This is ideal for comparing a single frequency across all common unit systems at once.
  • Increase the decimal places setting when converting between units with irrational conversion factors, such as rad/s (which involves π). The tool automatically switches to scientific notation when results fall below 0.0001 or exceed one trillion.
  • Use the Swap button to reverse a conversion instantly, verifying that round-trip results match the original input within the selected precision.
  • The conversion history panel records your last 10 conversions during the session. Click any history entry to restore those values as the current input, making it easy to compare frequencies from multiple specifications in sequence.
  • Remember that RPM, BPM, and cpm are all numerically equivalent (they differ only in context: rotation, musical beat, or generic cycle). FPS and RPS are both numerically equivalent to Hz. Choose the unit that matches your application domain.

Frequently Asked Questions

Is the Frequency Converter free?

Yes, Frequency Converter is totally free :)

Can I use the Frequency Converter offline?

Yes, you can install the webapp as PWA.

Is it safe to use Frequency Converter?

Yes, any data related to Frequency Converter only stored in your browser (if storage required). You can simply clear browser cache to clear all the stored data. We do not store any data on server.

What frequency units does this converter support?

The Frequency Converter supports 13 units across three groups: SI (Hz, kHz, MHz, GHz, THz), Rotational/Audio (RPM, RPS, BPM), and Time-Based/Angular (cpm, cph, rad/s, FPS, °/s). All conversions use Hertz (Hz) as the normalized base unit for maximum accuracy.

What is the difference between Hertz and RPM?

Hertz (Hz) measures frequency as cycles per second, while RPM (revolutions per minute) measures rotational speed as full rotations per minute. Since there are 60 seconds in a minute, 1 Hz = 60 RPM. For example, a motor spinning at 3000 RPM operates at 50 Hz. Both measure periodic events, but Hz is the SI standard used in physics and electronics, while RPM is preferred in mechanical engineering and automotive contexts.

How does angular frequency (rad/s) relate to Hertz?

Angular frequency in radians per second is related to Hertz by the factor 2π. Specifically, ω = 2πf, where ω is the angular frequency in rad/s and f is the frequency in Hz. Therefore, 1 Hz = 2π rad/s ≈ 6.2832 rad/s. Angular frequency is used extensively in physics, signal processing, and control systems because it simplifies many mathematical expressions involving trigonometric and exponential functions.

What is a Terahertz and where is it used?

A Terahertz (THz) equals one trillion Hertz (10¹² Hz). Terahertz radiation occupies the electromagnetic spectrum between microwave and infrared frequencies, roughly 0.1 to 10 THz. It is used in spectroscopy for material identification, security imaging systems at airports, quality control in pharmaceutical manufacturing, and emerging high-speed wireless communication research. Terahertz waves can penetrate many non-metallic materials without the ionization risks of X-rays.

Why is Hz used as the base unit for frequency conversion?

Hertz (Hz) is the SI unit of frequency, defined as one cycle per second. It is derived directly from the SI base unit of time (the second). Using Hz as the intermediate base ensures all conversions remain consistent with international standards. Every other unit is converted to Hz first, then to the target unit — this two-step normalization avoids rounding errors from chained conversions and keeps the conversion logic simple and maintainable.

What is BPM and how does it relate to frequency?

BPM (beats per minute) is the standard unit for musical tempo. Like RPM, it measures events per minute rather than per second, so 1 BPM = 1/60 Hz. A typical pop song at 120 BPM has a beat frequency of 2 Hz. BPM is universally used in music production, DJing, and exercise science (for heart rate). Converting BPM to Hz is useful in signal processing applications such as beat detection algorithms and audio synchronization.