This study demonstrates a general correlation to predict the saturated flow boiling heat transfer of R410A in horizontal macro- and mini-channels. The experimental data were observed in various tube diameters of 1.5, 3.0, 6.61, and 7.49 mm, mass fluxes of 100–600 kg/m2s, heat fluxes of 10–40 kW/m2, saturation temperatures of 5°C–15°C, and vapor qualities from 0.2 to 1. The database was compared with numerous well-known correlations. The proposed correlation was based on the superposition model of nucleate boiling and forced convective boiling contribution. The new modified correlation showed a good prediction against the present database.