Value of gas constant $R$ is .

The numerical value of R depends upon the units in which pressure and volume are expressed. When pressure is expressed in atmosphere and volume in litres, then the value of R at STP for 1 mole of gas is
$R=\frac{\text{1 atm}\times 22.414L}{\text{1 mole}\times 273.15K}$
$=0.082{\text{ L atm K}}^{-1}{\text{mol}}^{-1}$