ΔE 14.1, fair: the same colour family, but not a straight swap. Dirty Grey is a little lighter, more muted, warmer than Olive Green.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 14). Dirty Grey is a little lighter, more muted, warmer than Olive Green.
The same difference applies the other way round: Olive Green is a little darker, more saturated, 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 Olive Green on the colour wheel See Dirty Grey on the colour wheel
All matches: Olive Green equivalents · Dirty Grey equivalents