ΔE 6.5, close: similar, with a visible difference side by side. Brown is a little lighter, more saturated than Chaotic Red. They are different kinds of paint: Army Painter Chaotic Red is an opaque base/layer paint and Green Stuff World Brown is an ink, glaze or transparent paint, so they won’t behave the same on the model even where the colour is close.
Usually, if you are not matching paint already on the model. Close match (ΔE 6). Brown is a little lighter, more saturated than Chaotic Red. They are different kinds of paint.
The same difference applies the other way round: Chaotic Red is a little darker, more muted.
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 Chaotic Red on the colour wheel See Brown on the colour wheel
All matches: Chaotic Red equivalents · Brown equivalents