ΔE 8.4, close: similar, with a visible difference side by side. Brown Wash is a little darker, more saturated, warmer than Agrax Earthshade.
✓ Herrick Games paint comparison chart lists these two as equivalents.
Usually, if you are not matching paint already on the model. Close match (ΔE 8). Brown Wash is a little darker, more saturated, warmer than Agrax Earthshade.
The same difference applies the other way round: Agrax Earthshade is a little lighter, more muted, cooler.
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 Agrax Earthshade on the colour wheel See Brown Wash on the colour wheel
All matches: Agrax Earthshade equivalents · Brown Wash equivalents