Math
Frequency Calculator
Convert between frequency (Hz, kHz, MHz, GHz), period (s, ms, us, ns), angular frequency (rad/s), and RPM. Shows electromagnetic and acoustic wavelength.
Frequency Calculator
Enter frequency in Hz, kHz, MHz, or GHz.
Must be greater than zero.
Frequency
60 Hz
Range: audio range
Frequency (kHz)
0.06 kHz
Frequency (MHz)
6.0000e-5 MHz
Frequency (GHz)
6.0000e-8 GHz
RPM
3,600 RPM
Period (s)
0.016667 s
Period (ms)
16.666667 ms
Period (us)
16,666.666667 us
Period (ns)
1.6667e+7 ns
Angular frequency
376.991118 rad/s
Wavelength (EM, vacuum)
4.9965e+6 m
Wavelength (sound, air 20 C)
5.716667 m
Frequently Asked Questions about the Frequency Calculator
What is the relationship between frequency and period?
They are reciprocals: f = 1 / T. If a signal repeats every 0.001 s (1 ms), its frequency is 1 / 0.001 = 1000 Hz, or 1 kHz. Likewise, a 60 Hz signal has a period of 1 / 60 s, about 16.67 ms.
How do I convert frequency to angular frequency?
Multiply by 2 pi. Angular frequency omega (in rad/s) equals 2 pi times frequency (in Hz). For example, 60 Hz becomes 2 pi x 60, or about 376.99 rad/s. To go the other way, divide angular frequency by 2 pi.
How do I convert RPM to Hz?
Divide RPM by 60, since there are 60 seconds in a minute. A motor spinning at 1800 RPM rotates 30 times per second, so its frequency is 30 Hz. To convert Hz to RPM, multiply by 60: 60 Hz x 60 = 3600 RPM.
What frequency range counts as audio?
Roughly 20 Hz to 20 kHz, the typical span of healthy human hearing. Below 20 Hz is sub-audio (felt more than heard), and above 20 kHz is ultrasonic. The calculator labels your input with the matching range, including RF, microwave, and millimeter wave for higher frequencies.
How is wavelength calculated from frequency?
Wavelength = wave speed divided by frequency. For electromagnetic waves in vacuum the calculator uses the speed of light (299,792,458 m/s), so 100 MHz gives about 3.00 m. For sound in dry air at 20 C it uses 343 m/s, so a 440 Hz tone has a wavelength of about 0.78 m.