About the Frequency Converter
This frequency converter turns a frequency in any common unit into all the others: hertz, kilohertz, megahertz, gigahertz, terahertz, revolutions per minute (RPM), revolutions per hour, radians per second and degrees per second. It also gives the period (time for one cycle) and the wavelength of an electromagnetic wave at that frequency.
Use it to convert a motor or fan speed in RPM to hertz for a variable-frequency drive, to express a radio or Wi-Fi band in MHz or GHz, to find the angular velocity (rad/s) for physics problems, or to work out the period of an audio tone or clock signal.
All conversions are exact: 1 Hz is one cycle per second, 60 RPM equals 1 Hz, and one revolution is 2π radians. Wavelength assumes propagation in a vacuum at 299,792,458 m/s; in cables, water or glass waves travel slower and the wavelength is shorter.
With the default inputs, the hertz is 60 Hz. Change any value above to recalculate instantly.
How to use the frequency converter
- 1Enter the frequency or rotational speed.
- 2Select its unit (Hz, kHz, MHz, GHz, RPM, rad/s…).
- 3Read the value in hertz and the other units.
- 4Check the period and wavelength outputs for timing or antenna work.
Formula and method
Frequency is cycles per second. The metric prefixes step by factors of 1,000: 1 kHz = 1,000 Hz, 1 MHz = 1,000,000 Hz, 1 GHz = 10⁹ Hz. Rotational speed in revolutions per minute is converted by dividing by 60, and angular velocity multiplies hertz by 2π because each revolution sweeps 2π radians.
The period T is the reciprocal of frequency. The wavelength λ is the speed of light, 299,792,458 m/s, divided by the frequency — valid for radio, light and other electromagnetic waves in a vacuum (air is within 0.03%).
- f
- Frequency in hertz (cycles per second)
- ω
- Angular velocity in radians per second
- T
- Period, seconds per cycle
- λ
- Wavelength; c = 299,792,458 m/s
Worked examples
Motor spinning at 3,600 RPM
3,600 ÷ 60 = 60 Hz, which is why a two-pole motor on a 60 Hz grid runs at 3,600 RPM. Angular velocity is 2π × 60 = 377 rad/s and each revolution takes 1/60 s = 16.67 ms.
Concert pitch A: 440 Hz
440 Hz is 440 × 60 = 26,400 cycles per minute, and one cycle lasts 1 ÷ 440 = 2.273 ms. In angular terms that is 2π × 440 = 2,764.6 rad/s.
Wi-Fi at 2.4 GHz
2.4 GHz is 2,400 MHz or 2.4 billion Hz. Its wavelength is 299,792,458 ÷ 2.4 × 10⁹ = 0.1249 m, about 12.5 cm.
Frequently asked questions
How do I convert RPM to Hz?+
Divide RPM by 60. For example, 1,800 RPM ÷ 60 = 30 Hz. To convert Hz to RPM, multiply by 60: a 50 Hz signal is 3,000 RPM.
How many MHz are in a GHz?+
One gigahertz equals 1,000 megahertz, and one megahertz equals 1,000 kilohertz. So 5.8 GHz is 5,800 MHz.
How do I convert Hz to rad/s?+
Multiply hertz by 2π (about 6.2832). A 50 Hz frequency is 314.16 rad/s. To go back, divide rad/s by 2π.
What is the period of a frequency?+
The period is the time for one complete cycle, equal to 1 divided by the frequency. At 50 Hz the period is 0.02 s (20 ms); at 1 MHz it is 1 µs.
How do I find the wavelength from frequency?+
Divide the speed of light (299,792,458 m/s) by the frequency in hertz. For FM radio at 100 MHz the wavelength is about 3.0 m.