ΔE 14.1, fair: the same colour family, but not a straight swap. Crimson is noticeably lighter, cooler than Pure Red.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 14). Crimson is noticeably lighter, cooler than Pure Red.
The same difference applies the other way round: Pure Red 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 Pure Red on the colour wheel See Crimson on the colour wheel
All matches: Pure Red equivalents · Crimson equivalents