ΔE 7.2, close: similar, with a visible difference side by side. Earth Brown is a little lighter than Leather Brown.
Usually, if you are not matching paint already on the model. Close match (ΔE 7). Earth Brown is a little lighter than Leather Brown.
The same difference applies the other way round: Leather Brown is a little darker.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See Leather Brown on the colour wheel See Earth Brown on the colour wheel
All matches: Leather Brown equivalents · Earth Brown equivalents