ΔE 10.2, fair: the same colour family, but not a straight swap. Dark Grey Blue is a little lighter, more saturated, warmer than Navy Blue.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 10). Dark Grey Blue is a little lighter, more saturated, warmer than Navy Blue.
The same difference applies the other way round: Navy Blue is a little darker, 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 Navy Blue on the colour wheel See Dark Grey Blue on the colour wheel
All matches: Navy Blue equivalents · Dark Grey Blue equivalents