The algorithm and its implementation of the leading zero anticipation (LZA) are very vital for the performance of a high-speed floating-point adder in today’s state of art microprocessor design. Unfortunately, in predicting “shift amount” by a conventional LZA design, the result could be off by one position. This paper presents a novel parallel error detection algorithm for a general-case LZA. The proposed approach enables parallel execution of conventional LZA and its error detection, so that the error-indication signal can be generated earlier in the stage of normalization, thus reducing the critical path and improving overall performance. The circuit implementation of this algorithm also shows its advantages of area and power compared with other previous work.