Frequency converter
Convert between any two of 5 frequency units. Conversion runs in your browser.
More detailsUnits covered · Everyday frequency conversions · Hertz is just "per second" · Where each scale turns up · RPM is a frequency
Units covered
| Unit | Symbol | In hertzs |
|---|---|---|
| Hertz | Hz | 1 |
| Kilohertz | kHz | 1,000 |
| Megahertz | MHz | 1,000,000 |
| Gigahertz | GHz | 1,000,000,000 |
| Revolution per minute | rpm | 0.01666667 |
Everyday frequency conversions
| 1 of these | Hz | kHz | MHz | rpm |
|---|---|---|---|---|
| Hertz | 1 | 0.001 | 0.000001 | 60 |
| Kilohertz | 1,000 | 1 | 0.001 | 60,000 |
| Megahertz | 1,000,000 | 1,000 | 1 | 60,000,000 |
| Revolution per minute | 0.01666667 | 0.00001666667 | 1.666667e-08 | 1 |
Each row is one of that unit, given in each of the others.
Hertz is just "per second"
One hertz is one cycle per second, so the unit is dimensionally the inverse of time. That is why frequency and period are reciprocals: a 50 Hz mains supply has a period of 20 milliseconds, and a 2.4 GHz radio has a period of about 0.42 nanoseconds. If you know one, dividing 1 by it gives the other.
Where each scale turns up
Mains electricity is 50 Hz in most of the world and 60 Hz in the Americas. Audio spans roughly 20 Hz to 20 kHz, the range of human hearing, and CD audio samples at 44.1 kHz — a little over twice the top of that range, because the Nyquist limit requires sampling at more than double the highest frequency you intend to reproduce. Wi-Fi and processor clocks are in the gigahertz, where a single cycle is short enough that the distance light travels in it becomes a design constraint: at 3 GHz, light moves about 10 cm per cycle.
RPM is a frequency
Revolutions per minute measures the same quantity in different units — one RPM is 1/60 Hz. Engines, hard drives and motors are specified this way by convention. A 7,200 RPM drive spins at 120 Hz, which is also why drive vibration tends to show up as a hum near that frequency.