ΔE 10.4, fair: the same colour family, but not a straight swap. Prussian Blue is a little darker, warmer than Military Blue.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 10). Prussian Blue is a little darker, warmer than Military Blue.
The same difference applies the other way round: Military Blue is a little lighter, 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 Military Blue on the colour wheel See Prussian Blue on the colour wheel
All matches: Military Blue equivalents · Prussian Blue equivalents