We consider the method of fast calculation of broadband fluxes and solar radiation intensity in the Earth's atmosphere, taking into account the gas absorption, aerosol scattering, and clouds. The spatial integration of radiative transfer equation is performed by the discrete ordinate technique (DISORT), the wavelength integration - by the method of k-distribution taking into account the spectral dependence of instrumental function of the filter, solar constant, and surface albedo. We studied the influence of cloud characteristics (by the example of liquid water clouds Cb and ScI) and different methods of accounting for surface albedo on the accuracy of calculation of the shortwave radiation intensity. A good agreement is obtained for shortwave fluxes, calculated with the use of exponential series and by the benchmark line-by-line method, as well as by calculations of other authors.