Frequency Unit Converter

How to use this calculator

Three inputs, six outputs.

Frequency is the number you’re starting with. Enter it in the input field. Works with decimals and large numbers.

From unit is your source unit. The dropdown includes: Hertz (Hz), Kilohertz (kHz), Megahertz (MHz), Gigahertz (GHz), Terahertz (THz), and RPM (revolutions per minute).

To unit is your target. Same list.

Click Calculate and the blue results panel shows your converted value plus all equivalent frequencies simultaneously: Hz, kHz, MHz, GHz, RPM, and period in milliseconds (ms). That last one, period, is how long each cycle takes. It’s the inverse of frequency and useful any time you’re thinking about timing rather than rate.

What frequency actually measures

Frequency is cycles per second. One hertz means one complete cycle every second. 1,000 Hz means 1,000 cycles per second. That’s it.

What counts as a “cycle” depends entirely on the context. For AC power, it’s one complete oscillation of the electrical wave from peak to trough and back. For a CPU, it’s one clock pulse, the basic heartbeat that times every instruction. For a radio wave, it’s one oscillation of the electromagnetic field. For a spinning motor, it’s one full revolution.

Period is the time version of the same measurement. If frequency is “how many times per second,” period is “how long does one time take.” They’re reciprocals:

Period (seconds) = 1 / Frequency (Hz)

A 1 Hz signal has a 1-second period. A 1 kHz signal has a 1 ms period. A 1 GHz signal has a 1 nanosecond period. As frequency doubles, period halves.

Frequency tells you the rate. Period tells you the timing. Engineers switch between the two constantly depending on whether they're designing for throughput or for timing constraints.

The formulas

All conversions go through Hz as the base unit.

RPM to Hz requires a division by 60 because RPM counts cycles per minute, not per second:

The period calculation:

So 1000 Hz gives a period of 1000 / 1000 = 1 ms. 1 MHz gives 1000 / 1,000,000 = 0.001 ms = 1 microsecond.

Full conversion table: Hz to all units

Hz	kHz	MHz	GHz	RPM	Period
1	0.001	0.000001	0.000000001	60	1,000 ms
10	0.01	0.00001	0.00000001	600	100 ms
50	0.05	0.00005	0.00000005	3,000	20 ms
60	0.06	0.00006	0.00000006	3,600	16.67 ms
100	0.1	0.0001	0.0000001	6,000	10 ms
440	0.44	0.00044	0.00000044	26,400	2.27 ms
1,000	1	0.001	0.000001	60,000	1 ms
10,000	10	0.01	0.00001	600,000	0.1 ms
100,000	100	0.1	0.0001	6,000,000	0.01 ms
1,000,000	1,000	1	0.001	60,000,000	0.001 ms

kHz to MHz and GHz: the electronics range

kHz	MHz	GHz	Period
1	0.001	0.000001	1 ms
10	0.01	0.00001	0.1 ms
100	0.1	0.0001	0.01 ms
500	0.5	0.0005	0.002 ms
1,000	1	0.001	0.001 ms
10,000	10	0.01	0.0001 ms
100,000	100	0.1	0.00001 ms
1,000,000	1,000	1	0.000001 ms (1 ns)

RPM to Hz: mechanical and motor conversions

This is the table mechanics, HVAC engineers, and motor technicians reach for most.

RPM	Hz	kHz	Period (ms)	Context
60	1.00	0.001	1,000	Very slow motor, 1 rev/sec
300	5.00	0.005	200	Low-speed pump
600	10.00	0.010	100	Slow fan or compressor
1,200	20.00	0.020	50	Induction motor (2-pole, 40Hz grid)
1,500	25.00	0.025	40	Induction motor (4-pole, 50Hz grid)
1,800	30.00	0.030	33.33	Induction motor (4-pole, 60Hz grid)
3,000	50.00	0.050	20	Induction motor (2-pole, 50Hz grid)
3,600	60.00	0.060	16.67	Induction motor (2-pole, 60Hz grid)
6,000	100.00	0.100	10	High-speed spindle
10,000	166.67	0.167	6	Racing engine redline
20,000	333.33	0.333	3	Turbine, high-speed dental drill
60,000	1,000.00	1.000	1	Turbocharger, precision spindle

Frequency ranges by application

Where each part of the spectrum actually lives.

Frequency range	Application	Notes
0.1 - 20 Hz	Seismic waves, infrasound	Below human hearing
20 - 20,000 Hz	Human hearing range	Audio, acoustics
50 / 60 Hz	AC mains power	50 Hz in Europe/Asia, 60 Hz in North America
20 Hz - 20 kHz	Audio electronics	Amplifiers, speakers, microphones
530 - 1,700 kHz	AM radio	Medium wave broadcast
3 - 30 MHz	Shortwave radio	HF band, international broadcast
30 - 300 MHz	FM radio, VHF TV	87.5-108 MHz for FM broadcast
300 MHz - 3 GHz	UHF TV, 4G LTE, WiFi	2.4 GHz WiFi, cellular bands
5 GHz	WiFi (5 GHz band)	802.11ac/ax, less congestion
1 - 6 GHz	CPU clock speeds	Modern processors, 3-5 GHz typical
24 - 77 GHz	Radar, 5G mmWave	Automotive radar, high-speed 5G
300 GHz - 3 THz	Terahertz imaging	Security scanners, research
430 - 750 THz	Visible light	Red (430 THz) to violet (750 THz)

Real-world examples

CPU clock speed to period

A processor running at 3.6 GHz. How long does each clock cycle take?

AC motor synchronous speed

An induction motor on a 50 Hz grid. What RPM does it run at for a 4-pole configuration?

Audio frequency to wavelength

A 440 Hz tone (concert A). What’s the wavelength in air?

Radio frequency band check

A radio operates at 98.5 MHz. What band is this?

Engine RPM to frequency

A car engine at redline: 7,200 RPM. What frequency is that?

Common mistakes people make

Confusing Hz with RPM by a factor of 60. The relationship is Hz = RPM / 60, full stop. 60 RPM = 1 Hz. 3,600 RPM = 60 Hz. People often try to use 1,000 as the conversion factor by analogy with the kHz/MHz/GHz chain, which gives completely wrong results. RPM is per minute; Hz is per second; the only factor is 60.

Misreading period units at high frequencies. The period output is in milliseconds. At 1 MHz, the period is 0.001 ms = 1 microsecond. At 1 GHz, it’s 0.000001 ms = 1 nanosecond. These numbers look small but represent very different timescales. Always note the unit prefix: microseconds (µs) and nanoseconds (ns) are 1,000× apart.

Treating CPU frequency as directly proportional to speed. A 4 GHz CPU is not necessarily twice as fast as a 2 GHz CPU. Modern processors execute multiple operations per clock cycle (instructions per cycle, IPC), and architecture matters as much as frequency. Clock frequency is one variable in a multi-variable equation. The calculator gives you frequency conversions correctly; what those frequencies mean for performance depends on the architecture.

Mixing frequency with sampling rate. Audio sample rates (44.1 kHz, 48 kHz, 96 kHz) are not audio frequencies. A 44.1 kHz sample rate means 44,100 samples per second. The actual audio frequencies captured are up to half the sample rate (Nyquist theorem), so 44.1 kHz sampling captures up to 22.05 kHz of audio. Entering a sample rate into a frequency converter and using the result to reason about audio content gives meaningless numbers.

Assuming all grid frequencies are 50 Hz or 60 Hz. North America, most of Central America, and parts of Japan use 60 Hz. Europe, Africa, Asia, most of South America, and the rest of Japan use 50 Hz. Importing electrical equipment across these regions affects motor speeds, timing circuits, and anything that uses the grid frequency as a reference. A 60 Hz motor on a 50 Hz grid runs 16.7% slower.

Period and frequency: the inverse relationship

The period output in the results panel is worth understanding because most frequency converters skip it.

Period = 1 / Frequency. That’s the complete relationship. But the practical consequences of that inversion aren’t always intuitive.

Doubling frequency halves the period. Tripling frequency reduces the period to one-third. The relationship is hyperbolic, not linear.

Frequency	Period
1 Hz	1,000 ms (1 second)
2 Hz	500 ms
4 Hz	250 ms
10 Hz	100 ms
100 Hz	10 ms
1 kHz	1 ms
10 kHz	0.1 ms (100 µs)
100 kHz	0.01 ms (10 µs)
1 MHz	0.001 ms (1 µs)
10 MHz	0.0001 ms (100 ns)
100 MHz	0.00001 ms (10 ns)
1 GHz	0.000001 ms (1 ns)
10 GHz	0.0000001 ms (0.1 ns)

Engineers working on timing-sensitive systems (microcontrollers, communications, motor control) think in period as naturally as they think in frequency. Setting a timer interrupt to fire every 5 ms? That’s a 200 Hz event. Running an SPI bus at 8 MHz? Each bit takes 125 nanoseconds. The calculator outputs both because the question “how long does one cycle take?” is often more useful than “how many cycles per second?”

The bottom line

Frequency is one concept wearing many different unit labels across completely different fields. 60 Hz from an AC power engineer, 60 RPM from a mechanical engineer, and 0.00006 MHz from a radio engineer are all the same underlying number. The calculator converts between them and adds the period because timing and rate are two sides of the same measurement.

Enter your frequency, pick your units, and read all the equivalent values at once. The period column is the one most people didn’t know they needed until they see it.