Frequency Unit Converter (Hz / kHz / MHz / GHz)
Pick any frequency unit — Hz, kHz, MHz, GHz, THz, rpm or bpm — type a value, and every other unit fills in instantly along with the period T = 1 / f, auto-scaled to s, ms, µs, ns or ps. SI prefixes use the exact decimal multipliers (10³, 10⁶, 10⁹, 10¹²) defined by the BIPM; rpm and bpm both convert as 1/60 Hz. Handy for radio, Wi-Fi, 5G band planning, CPU clock speeds, audio sample rates, motor speeds and music tempos.
Please enter a valid number
Live value in every frequency unit
Period T = 1 / f —
Tip: SI prefixes (kilo / mega / giga / tera) are exact decimal multiples 10³ / 10⁶ / 10⁹ / 10¹². 1 rpm and 1 bpm both equal 1/60 Hz — arithmetically identical, just used in different fields (rotational vs musical).
- Hz Mains power (50 Hz HK/EU, 60 Hz US), low-frequency audio
- kHz AM radio, long-wave, audio sample rates
- MHz FM radio, early CPU clocks, radio links
- GHz Wi-Fi (2.4 / 5 / 6 GHz), 5G, modern CPUs
- rpm Engine speed, motors, HDD spindles, turntables
- bpm Music tempo, heart rate, metronomes
—
Formula
1 kHz = 10³ Hz, 1 MHz = 10⁶ Hz, 1 GHz = 10⁹ Hz, 1 THz = 10¹² Hz 1 rpm = 1 bpm = 1/60 Hz T (seconds) = 1 / f (Hz)
- · SI prefixes (kilo / mega / giga / tera) are exact decimal multipliers 10³ / 10⁶ / 10⁹ / 10¹² — they are not the binary KiB / MiB used for digital storage, so no factor of 1 024 sneaks in.
- · rpm (revolutions per minute) and bpm (beats per minute) are mathematically identical at 1 / 60 Hz; they are listed separately only because the rotational and musical communities prefer their own labels.
- · Period T = 1 / f gives an intuitive sense of scale: 50 Hz mains = 20 ms per cycle, 1 MHz = 1 µs, a 2.4 GHz Wi-Fi cycle is ≈ 417 ps.
- · Useful reference points: mains 50 Hz (HK/EU) / 60 Hz (US/JP), AM band 535–1 605 kHz, FM band 88–108 MHz, Wi-Fi 2.4 / 5 / 6 GHz, mid-band 5G ≈ 3.5 GHz, visible light ≈ 430–770 THz.
- · Source: BIPM SI Brochure (9th ed., 2019) defines the hertz (Hz = s⁻¹) and the SI prefixes.
- · The conversion is pure ratio arithmetic — no wave speed, medium or temperature involved. If you need wavelength, use the Wavelength ↔ Frequency calculator under Science.
Frequently asked
Is 1 MHz really 1 000 000 Hz or 1 048 576 Hz?
It is exactly 1 000 000 Hz. The binary prefixes (1 KiB = 1024 bytes) only apply to digital storage. For time, frequency, electricity and light, "mega" is always 10⁶ as defined by the BIPM SI Brochure. So a CPU labelled 4.5 GHz really runs at 4 500 000 000 cycles per second, not 4 831 838 208.
How can rpm and Hz be interchangeable? What does engine speed have to do with frequency?
Frequency just means "events per second". A full revolution is one repeating event, so rpm = events per minute = events / 60 seconds = (rpm / 60) Hz. A 7 200 rpm hard-drive spindle spins at 120 Hz, i.e. 120 turns per second. By the same logic, 120 bpm (music tempo) is 2 Hz — two beats every second.
CPU GHz, Wi-Fi GHz, 5G GHz — can I compare the numbers?
The unit is identical (1 GHz = 10⁹ Hz), so the numbers are directly comparable, but the physical meaning differs. CPU GHz counts clock cycles per second; Wi-Fi / 5G GHz is the carrier frequency, i.e. how many times the radio wave oscillates each second. A 4 GHz CPU and a 4 GHz radio wave have no causal link — they just happen to land on the same point of the frequency axis.
How are frequency and wavelength related, and does this tool compute wavelength?
Wavelength λ = v / f, where v is the wave speed in the medium (c ≈ 2.998 × 10⁸ m/s in vacuum for light, ≈ 343 m/s in air for sound). For example, 100 MHz FM in vacuum has λ ≈ 3 m and 2.4 GHz Wi-Fi has λ ≈ 12.5 cm. This widget only converts between frequency units (no medium needed); for wavelength, use the Wavelength ↔ Frequency calculator under Science.
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