ΔE 11.7, fair: the same colour family, but not a straight swap. Olive Green is a little lighter, more muted than Sap Green.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 12). Olive Green is a little lighter, more muted than Sap Green.
The same difference applies the other way round: Sap Green is a little darker, more saturated.
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 Sap Green on the colour wheel See Olive Green on the colour wheel
All matches: Sap Green equivalents · Olive Green equivalents