There has been considerable interest in CVD to utilize rotating disk, stagnation point, and impinging jet flows to achieve large area film thickness and composition uniformity, as well as to conduct kinetic experiments. The present study explores the limits of the classical one‐dimensional treatment for typical CVD reactor configurations and flows by comparison with the complete two‐dimensional axisymmetric description. The one and two‐dimensional balance equations for flow, energy, and chemical species are solved numerically by the Galerkin finite element method. The comparisons are presented in terms of the size of the deposition surface where the classical analysis is correct within 5% for varying reactor size parameters, flow rates, pressures, and gases. The results demonstrate that the one‐dimensional treatment is valid over a wide range of conditions and radial distances. When it fails, the primary reasons are thermal recirculation and edge effects. The general results should provide guidelines for designing kinetic studies as well as commercial CVD reactor equipment.