Enthalpies of formation for 14 C2-C4 fluorinated hydrocarbons were calculated with nine popular ab initio and density functional theory methods: B3LYP, CBS-QB3, CBS-APNO, M06, M06-2X, omega B97X, G4, G4(MP2)-6X, and W1U via several series of isodesmic reactions. The recommended ideal gas phase Delta H-f298 degrees (kcal mol(-1)) values calculated in this study are the following: -65.4 for CH3CH2F; -70.2 for CH3CH2CH2F; -75.3 for CH3CHFCH3; -75.2 for CH(3)CH(2)CH(2)CH2F; -80.3 for CH3CHFCH2CH3; -108.1 for CH2F2; -120.9 for CH3CHF2; -125.8 for CH3CH2CHF2; -133.3 for CH3CF2CH3; -166.7 for CHF3; -180.5 for CH3CF3; -185.5 for CH3CH2CF3; -223.2 for CF4; and -85.8 for (CH3)(3)CF. Entropies (S298 degrees in cal mol(-1) K1) were estimated using B3LYP/6-31+G(d,p) computed frequencies and geometries. Rotational barriers were determined and hindered internal rotational contributions for S298 degrees, and C-p(T) were calculated using the rigid rotor harmonic oscillator approximation, with direct integration over energy levels of the intramolecular rotation potential energy curve. Thermochemical properties for the fluorinated carbon groups C/C/F/H-2, C/C-2/F/H, C/C/F-2/H, C/C-2/F-2, and C/C/F-3 were derived from the above target fluorocarbons. Previously published enthalpies and groups for 1,2-difluoroethane, 1,1,2-trifluoroethane, 1,1,2,2-tetrafluoroethane, 1,1,1,2-tetrafluoroethane, 1,1,1,2,2-pentafluoroethane, 2-fluoro-2-methylpropane that were previously determined via work reaction schemes are revised using updated reference species values. Standard deviations are compared for the calculation methods.