ΔE 9.1, close: similar, with a visible difference side by side. German Gray is a little lighter, more muted, cooler than Navy Blue.
Usually, if you are not matching paint already on the model. Close match (ΔE 9). German Gray is a little lighter, more muted, cooler than Navy Blue.
The same difference applies the other way round: Navy Blue is a little darker, more saturated, warmer.
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 German Gray on the colour wheel
All matches: Navy Blue equivalents · German Gray equivalents