An accurate estimator of chirp rate and initial frequency of the linear frequency modulation (LFM) signals based on modified discrete chirp Fourier transform (MDCFT) is investigated in this study. The proposed algorithm consists of two banks, namely coarse search and fine search. The coarse search returns a coarse estimate of the parameter by addressing the maximum MDCFT coefficient of a LFM signal. The coarse estimate is refined by fine search algorithms, including spectrum slices and iterative interpolation methods. Compared to conventional fine search approaches, spectrum slices and iterative interpolation methods are always more efficient because they utilize more prior information about the MDCFT results, thus requiring fewer extra computations. Finally, computer simulations are conducted to evaluate the performance of our algorithms by comparison with the Cramer–Rao lower bound. The proposed estimator shows robust performance for various values of the signal parameters with the addition in the additive white Gaussian noise.