Count the number of complete cycles in a given time
Divide the number of cycles by the time taken
Use the formula: frequency = 1 / period
Measure the period of one complete cycle
Convert the period into seconds
Calculate frequency in hertz using f = 1 / T
For waves, use frequency = wave speed / wavelength
Measure the wave speed
Measure the wavelength
Divide wave speed by wavelength
For rotating objects, count rotations per second
For periodic signals, use an oscilloscope or frequency meter
Read the frequency directly from the instrument