This paper presents a high-precision algorithm for the forward and inverse MDCT computations using the unified recursive architecture. In this algorithm, the kernel transform of MDCT/IMDCT can share the same architecture because the coefficients for the recursive formula are the same. The preprocessed input samples in the proposed algorithm allow a lower dynamic range than those of other recursive algorithms. Therefore, the proposed algorithm outperforms other MDCT/IMDCT designs in terms of memory storage size, computing cycles and fixed point error if a VLSI implementation of the MDCT/IMDCT is used for MPEG audio coding standards.