As variable delays are observed in the integrated circuits under different data inputs, it is expected to enhance the performance of the circuit using the average-case design methodology. This paper presents a novel approach using the time-domain multistage speculation to realize a variable-latency circuit, in which speculation points with double-sampling and check-recovery units are inserted into the critical path to enhance the performance. Furthermore, a design framework is implemented to convert a original circuit into the new one automatically. Experimental results showed that a 1.79 – 4.42 speedup in a 64-bit ripple carry adder and up to 30.5% throughput enhancements in several ISCAS and MCNC benchmarks with reasonable area overheads.