ΔE 30.0, loose: different enough that you should pick on purpose. Blue is noticeably lighter, cooler than Purple Swarm.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 30). Blue is noticeably lighter, cooler than Purple Swarm.
The same difference applies the other way round: Purple Swarm is noticeably 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 Purple Swarm on the colour wheel See Blue on the colour wheel
All matches: Purple Swarm equivalents · Blue equivalents