A frequency calibrator includes an input signal generator configured to generate an input signal based on an oscillation signal and an external signal; a frequency difference extractor configured to extract, from the input signal, a frequency difference signal having a frequency corresponding to a frequency difference between an external frequency of the external signal and an oscillation frequency of the oscillation signal; a divider configured to generate a division signal by dividing a signal having the oscillation frequency by a division ratio; and a frequency tuner configured to tune the oscillation frequency of the oscillation signal based on a result of comparing the frequency difference signal to the division signal.