Frequency converter — hertz, kilohertz, megahertz and RPM

Clock speeds, audio frequencies, engine revolutions and metronome tempo all describe how often something repeats — the same quantity wearing different clothes.

How to use it

1
Type into any row — say Hz or kHz. The results appear immediately, no button needed.
2
Need a combined figure? Fill in two rows, for example Hz and MHz, and they are added together before converting.
3
Set how many digits you want (4–12) and click a result to copy the plain number.

Exact conversion factors

These are the definitions the calculator uses. Nothing here is rounded for convenience — where a value is exact by definition, it says so.

1 kHz = 1000 Hz · 1 MHz = 1 000 000 Hz · 1 GHz = 10⁹ Hz
1 RPM = 0.0166666667 Hz · 3000 RPM = 50 Hz · 1800 RPM = 30 Hz
120 BPM = 2 Hz = 500 ms per beat · 140 BPM = 428.571 ms
50 Hz mains = 20 ms period · 60 Hz mains = 16.667 ms

FormulaHz = kHz × 1000 = MHz × 10⁶ = GHz × 10⁹ · Hz = RPM ÷ 60 · period (s) = 1 ÷ Hz

Frequency conversion table — every unit

One of each unit, converted into the three units people ask for most.

Unit	Hz	kHz	MHz
1 GHz	1 000 000 000 Hz	1 000 000 kHz	1 000 MHz
1 MHz	1 000 000 Hz	1 000 kHz	1 MHz
1 kHz	1 000 Hz	1 kHz	0.001 MHz
1 Hz	1 Hz	0.001 kHz	0.000001 MHz
1 RPM	0.0166667 Hz	0.0000166667 kHz	0.0000000166667 MHz
1 BPM	0.0166667 Hz	0.0000166667 kHz	0.0000000166667 MHz
1 °/s	0.00277778 Hz	0.00000277778 kHz	0.00000000277778 MHz

Hz → kHz, MHz — quick values

Hz	kHz	MHz
0.5 Hz	0.0005 kHz	0.0000005 MHz
1 Hz	0.001 kHz	0.000001 MHz
2 Hz	0.002 kHz	0.000002 MHz
3 Hz	0.003 kHz	0.000003 MHz
5 Hz	0.005 kHz	0.000005 MHz
10 Hz	0.01 kHz	0.00001 MHz
20 Hz	0.02 kHz	0.00002 MHz
25 Hz	0.025 kHz	0.000025 MHz
50 Hz	0.05 kHz	0.00005 MHz
100 Hz	0.1 kHz	0.0001 MHz
250 Hz	0.25 kHz	0.00025 MHz
1 000 Hz	1 kHz	0.001 MHz

How this converter works

The metric side is simple decimal stepping: 1 GHz is 1000 MHz is a billion hertz. The useful trick is the rotational side — RPM divided by 60 gives hertz, so an engine at 3000 RPM is turning at 50 Hz, the same rate as European mains electricity.

Beats per minute sits on the same scale, which lets you match a tempo to a delay time: 120 BPM is 2 Hz, so a quarter note lasts 500 ms — the number audio engineers dial into delay units.

Notes and abbreviations

1 Hz = one cycle per second; 1 kHz = 1000 Hz; 1 MHz = 10⁶ Hz
RPM ÷ 60 = Hz — engine and motor speeds
120 BPM = 2 Hz = 500 ms per beat

Questions

How do I convert RPM to Hz?

Divide by 60. 1800 RPM is 30 Hz.

What is the delay time for 140 BPM?

140 BPM is 2.3333 Hz, so one beat is 428.57 ms. Halve it for eighths, quarter it for sixteenths.

Does this cover wavelength?

Not directly. Divide the speed of light, 299 792 458 m/s, by the frequency in hertz to get metres.