In this paper, an algorithm based on Taylor series expansion is proposed to calculate the logarithm (log(2)x) of IEEE754 binary32 accuracy floating-point number by a multi-domain partitioning method. The general mantissa (1 <= x < 2) is multiplied by 2, 4, 8, . . . (or equivalently left-shifted by 1, 2, 3, . . . bits), the regions of (2 <= x < 4), (4 <= x < 8), (8 <= x < 16); . . . are considered, and Taylor-series expansion is applied. In those regions, the slope of f (x) = log(2)x with respect to x is gentle compared to the region of (1 <= x < 2), which reduces the required number of terms. We also consider the trade-o ffs among the numbers of additions, subtractions, and multiplications and Look-Up Table (LUT) size in hardware to select the best algorithm for the engineer's design and build the best hardware device.