ΔE 16.6, loose: different enough that you should pick on purpose. Celestra Grey is a little lighter, more muted, cooler than Light Grey Green.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 17). Celestra Grey is a little lighter, more muted, cooler than Light Grey Green.
The same difference applies the other way round: Light Grey Green is a little darker, 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 Light Grey Green on the colour wheel See Celestra Grey on the colour wheel
All matches: Light Grey Green equivalents · Celestra Grey equivalents