ΔE 13.8, fair: the same colour family, but not a straight swap. Viking Grey is a little darker than Graphite Green.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 14). Viking Grey is a little darker than Graphite Green.
The same difference applies the other way round: Graphite Green is a little lighter.
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 Graphite Green on the colour wheel See Viking Grey on the colour wheel
All matches: Graphite Green equivalents · Viking Grey equivalents