Electric Lime vs Army Green

How close are they?

ΔE 28.3, loose: different enough that you should pick on purpose. Army Green is noticeably darker, much more muted than Electric Lime.

Can I use Army Green instead of Electric Lime?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 28). Army Green is noticeably darker, much more muted than Electric Lime.

Can I use Electric Lime instead of Army Green?

The same difference applies the other way round: Electric Lime is noticeably lighter, much more saturated.

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.