Classical Monte Carlo (MC) simulations for laser-Doppler flowmetry (LDF) often necessitate too long computation times and specialized hardware. This is particularly true for LDF at large interoptode spacing with low absorption coefficients and large anisotropic factors representing real biological tissues. For this reason, a random numbers free "analytical" implementation of the classical MC (MC_an) is proposed. The MC_an approach allows to obtain noise exempt LDF spectra in a short time and with a simple personal laptop. The proposed MC_an holds for a diffusive regime of light propagation and it is practically implemented for a semi-infinite geometry. Its validity is demonstrated by comparisons with the classical MC.