Multiplane light conversion (MPLC) offers an alternative to adaptive optics for coupling a turbulence-corrupted free-space optical beam into single-mode fiber or waveguide. Recent published test results suggest that such a conversion device has comparable or better performance than an adaptive optics system. To better understand the device characteristics, simulations were conducted to quantify the power loss for different turbulence strengths and the number of Hermite–Gaussian modes used in the conversion process. The specific case studied is a prototype free-space laser communication system developed by the U.S. Army Research Laboratory. Simulation and statistical results of the conversion performance are reported. Analysis of a beam power combiner after MPLC is also discussed.