ΔE 10.1, fair: the same colour family, but not a straight swap. Brown is a little lighter, more muted than Pure Red.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 10). Brown is a little lighter, more muted than Pure Red.
The same difference applies the other way round: Pure Red is a little darker, 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 Pure Red on the colour wheel See Brown on the colour wheel
All matches: Pure Red equivalents · Brown equivalents