The principle and features of 5 kinds of typical and mature electric energy metering algorithms are introduced simply. Then the 5 algorithms are used to meter total electric energy, fundamental energy and harmonic energy under non-synchronous and synchronous conditions. So the relative errors and calculating times can be got. In general, the relative errors are smaller when using Nuttall window double-spectrum-line interpolation based FFT algorithm, Rife-Vincent window double-spectrum-line interpolation based FFT algorithm and wavelet packet decomposition and reconstruction algorithm to compute total electric energy, while the relative errors are smaller when using Prony algorithm and quasi-synchronous sampling based FFT algorithm to compute harmonic energy. And Nuttall window double-spectrum-line interpolation based FFT algorithm and Rife-Vincent window double-spectrum-line interpolation based FFT algorithm has better real time performance than the 3 algorithms. These conclusions can be used in practice.