The hybrid density-functional theory (DFT) calculated energies Of C-1-C-16 straight-chain alkanes were obtained based on B3LYP/6-311++G(3df,2pd) single-point energies and the related thermal corrections of B3LYP/6-31G(d,p) optimized geometries. A 3-parameter modification equation and the least-squares approach are adopted to calibrate all the molecular calculated energies to produce accurate enthalpies of formation (DeltaH(f)) and Gibbs free energies of formation (DeltaG(f)), respectively. This study found that all compounds had 0.04% average relative error (A.R.E.) for the atomization energies, with a mean value of absolute error (M.A.E.) of just 1.1 kJ/mol for the DeltaH(f) and 1.9 kJ/mol for the DeltaG(f) of formation. The DeltaH(f) values obtained in this work are superior to the improved G3(MP2)//B3LYP calculations for the same 16 alkanes in pertinent literature.