The ideal gas constant is a constant found in the ideal gas law: R=NAkB=8.315 K/J=1.986 cal/K=0.0821 l×atm/K\begin{align} R=N_{A}k_{B}&=8.315\ \text{K/J} \\ &=1.986\text{ cal/K} \\ &=0.0821\text{ l}\times \text{atm/K} \end{align}R=NAkB=8.315 K/J=1.986 cal/K=0.0821 l×atm/K NAN_{A}NA is the Avogadro number and kBk_{B}kB is the Boltzmann constant.