To approximate the exact peaks of continuous-time orthogonal frequency division multiplexing (OFDM) signals, four times oversampling is usually employed for discrete-time OFDM signals in various peak-to-average power ratio (PAPR) reduction schemes. Such an oversampling process would significantly increase the computational complexity, especially for a selected mapping scheme where a number of IFFT blocks may be used. In this paper, we present a low-complexity PAPR estimation scheme with two times oversampling based on "peak-search-and-partial-interpolation" (PSPI). As compared to the PAPR estimation method with four times oversampling, the proposed one achieves similar performance with only about half computational complexity. It is also shown that, with no significant increase in the computational complexity, the proposed PSPI scheme with two times oversampling has better PAPR estimation performance than the previous PSPI work without oversampling.