ΔE 24.7, loose: different enough that you should pick on purpose. Jade Green is noticeably lighter, more saturated, cooler than Grass Green.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 25). Jade Green is noticeably lighter, more saturated, cooler than Grass Green.
The same difference applies the other way round: Grass Green is noticeably darker, more muted, 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 Grass Green on the colour wheel See Jade Green on the colour wheel
All matches: Grass Green equivalents · Jade Green equivalents