We present a reliable method to define the interfacial particles for determining the crystal−melt interface position, which is the key step for the crystal−melt interfacial free energy calculations using capillary wave approach. Using this method, we have calculated the free energies γ of the fcc crystal-melt interfaces for the hard-sphere system as a function of crystal orientations by examining the height fluctuations of the interface using Monte Carlo simulations. We find that the average interfacial free energy γ0 = 0.62 ± 0.02kBT/σ2 and the anisotropy of the interfacial free energies are weak, γ100 = 0.64 ± 0.02, γ110 = 0.62 ± 0.02, γ111 = 0.61 ± 0.02kBT/σ2. The results are in good agreement with previous simulation results based on the calculations of the reversible work required to create the interfaces (Davidchack and Laird, Phys. Rev. Lett. 2000,85, 4571). In addition, our results indicate γ100 > γ110 > γ111 for the hard-sphere system, similar to the results of the Lennard−Jones system.