The tables below have been prepared from the professional units conversion program Uconeer by Katmar Software. These tables contain 188 values for the Universal Gas Constant in the most likely combinations of units. These include the most commonly used values for the universal gas constant when working in metric units, SI units, English engineering units and US customary units.
However, the dedicated Gas Constant calculator in Uconeer calculates the value of "R" based on over 900 combinations of units, so if you don't find what you want here please go to the Uconeer main page to read the program description and to download the program. Uconeer will even allow you to add your own units, so if you do not find the units you need in the tables below, or built into Uconeer, you can add them in for yourself.
In addition to the Universal Gas Constant calculator, Uconeer includes a gas flowrate converter which will calculate gas density and convert between volume and mass. Uconeer contains over 450 units in 48 categories, and includes several other special converters and calculators.
Gas Constant Values based on Energy Units 
If you are using kg mol as the unit for quantity of matter then multiply the appropriate value in the g mol column by 1000. 
g mol Kelvin 
lb mol Kelvin 
g mol Rankine 
lb mol Rankine 

Btu  0.0078806  3.57458  0.00437811  1.98588 
cal  1.98588  900.779  1.10327  500.433 
Chu  0.00437811  1.98588  0.00243228  1.10327 
erg  8.31447e+7  3.77138e+10  4.61915e+7  2.09521e+10 
ft.lbf  6.13244  2781.63  3.40691  1545.35 
hp.h  3.09719e6  0.00140486  1.72066e6  0.000780479 
J  8.31447  3771.38  4.61915  2095.21 
kcal  0.00198588  0.900779  0.00110327  0.500433 
kgf.m  0.847840  384.574  0.471022  213.652 
kJ  0.00831447  3.77138  0.00461915  2.09521 
kW.h  2.30958e6  0.00104761  1.2831e6  0.000582003 
N.m  8.31447  3771.38  4.61915  2095.21 
Gas Constant Values based on Pressure and Volume Units 
This table is based on g moles as the unit for quantity of matter and Kelvin as the unit for temperature. If you are using kg mol as the unit for quantity of matter then multiply the value given below by 1000. 
cm^3  liter  m^3  ft^3  inch^3  
atm  82.0575  0.0820575  8.20575e5  0.00289783  5.00745 
bar  83.1447  0.0831447  8.31447e5  0.00293623  5.0738 
foot H2O  2781.63  2.78163  0.00278163  0.0982323  169.745 
inch H2O  33379.5  33.3795  0.0333795  1.17879  2036.94 
inch Hg  2455.27  2.45527  0.00245527  0.086707  149.83 
kgf/cm^2  84.7840  0.0847840  8.47840e5  0.00299412  5.17384 
kPa  8314.47  8.31447  0.00831447  0.293623  507.38 
lbf/ft^2  173651  173.651  0.173651  6.13244  10596.9 
mbar  83144.7  83.1447  0.0831447  2.93623  5073.8 
meter H2O  847.840  0.847840  0.00084784  0.0299412  51.7384 
mm H2O  847840  847.840  0.847840  29.9412  51738.4 
mm Hg  62363.8  62.3638  0.0623638  2.20236  3805.68 
Pa  8.31447e+6  8314.47  8.31447  293.623  507380 
PSI  1205.91  1.20591  0.00120591  0.0425864  73.5893 
Gas Constant Values based on Pressure and Volume Units 
This table is based on lb moles as the unit for quantity of matter and Rankine as the unit for temperature. 
cm^3  liter  m^3  ft^3  inch^3  
atm  20678.1  20.6781  0.0206781  0.730241  1261.86 
bar  20952.1  20.9521  0.0209521  0.739917  1278.58 
foot H2O  700958  700.958  0.700958  24.7541  42775.1 
inch H2O  8.41150e+6  8411.50  8.41150  297.049  513301 
inch Hg  618717  618.717  0.618717  21.8498  37756.5 
kgf/cm^2  21365.2  21.3652  0.0213652  0.754505  1303.79 
kPa  2.09521e+6  2095.21  2.09521  73.9917  127858 
lbf/ft^2  4.37594e+7  43759.4  43.7594  1545.35  2.67036e+6 
mbar  2.09521e+7  20952.1  20.9521  739.917  1.27858e+6 
meter H2O  213652  213.652  0.213652  7.54505  13037.9 
mm H2O  2.13652e+8  213652  213.652  7545.05  1.30379e+7 
mm Hg  1.57154e+7  15715.4  15.7154  554.985  959014 
Pa  2.09521e+9  2.09521e+6  2095.21  73991.7  1.27858e+8 
PSI  303885  303.885  0.303885  10.7316  18544.2 