ΔE 8.2, close: similar, with a visible difference side by side. Medium Gray is a little lighter, cooler than Gray FS36118.
Usually, if you are not matching paint already on the model. Close match (ΔE 8). Medium Gray is a little lighter, cooler than Gray FS36118.
The same difference applies the other way round: Gray FS36118 is a little darker, 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 Gray FS36118 on the colour wheel See Medium Gray on the colour wheel
All matches: Gray FS36118 equivalents · Medium Gray equivalents