The ratio of SI unit to CGS unit of a physical constant is ${10}^{-7}$. That constant is

Universal gas constant:

$\mathrm{R}=\left[{\mathrm{M}}^1{\mathrm{L}}^2{ \mathrm{T}}^{-2}{ \mathrm{K}}^{-1}\right]$

${\left(\frac{\mathrm{SI}}{\mathrm{CGS}}\right)}_{\mathrm{R}}=\frac{1}{{\left(1000\right)}^1{\left(100\right)}^2{\left(1\right)}^{-2}{\left(1\right)}^{-1}}={10}^{-7}$

Universal gravitational constant:

$\mathrm{G}=\left[{\mathrm{M}}^{-1}{ \mathrm{T}}^{-2}{ \mathrm{L}}^3\right]$

${\left[\frac{\mathrm{SI}}{\mathrm{CGS}}\right]}_{\mathrm{G}}=\left(1000{)}^1\right(1{)}^{-2}(100{)}^{-3}={10}^{-3}$