ΔE 9.9, close: similar, with a visible difference side by side. Grotesque Green is more muted, cooler than Rotten Flesh.
Usually, if you are not matching paint already on the model. Close match (ΔE 10). Grotesque Green is more muted, cooler than Rotten Flesh.
The same difference applies the other way round: Rotten Flesh 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 Rotten Flesh on the colour wheel See Grotesque Green on the colour wheel
All matches: Rotten Flesh equivalents · Grotesque Green equivalents