ΔE 7.6, close: similar, with a visible difference side by side. Leather Brown is a little darker, more muted than Base Flesh.
Usually, if you are not matching paint already on the model. Close match (ΔE 8). Leather Brown is a little darker, more muted than Base Flesh.
The same difference applies the other way round: Base Flesh is a little lighter, more saturated.
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 Base Flesh on the colour wheel See Leather Brown on the colour wheel
All matches: Base Flesh equivalents · Leather Brown equivalents