ΔE 11.4, fair: the same colour family, but not a straight swap. Merm Green is more muted, cooler than Steel Helmet Green.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 11). Merm Green is more muted, cooler than Steel Helmet Green.
The same difference applies the other way round: Steel Helmet Green is 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 Steel Helmet Green on the colour wheel See Merm Green on the colour wheel
All matches: Steel Helmet Green equivalents · Merm Green equivalents