ΔE 10.9, fair: the same colour family, but not a straight swap. N7 Neutral Gray is a little lighter, more muted than Grey Castle.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 11). N7 Neutral Gray is a little lighter, more muted than Grey Castle.
The same difference applies the other way round: Grey Castle 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 Grey Castle on the colour wheel See N7 Neutral Gray on the colour wheel
All matches: Grey Castle equivalents · N7 Neutral Gray equivalents