ΔE 13.3, fair: the same colour family, but not a straight swap. Prussian Blue is a little lighter, more muted, cooler than Navy Blue.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 13). Prussian Blue 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 Prussian Blue on the colour wheel
All matches: Navy Blue equivalents · Prussian Blue equivalents