ΔE 11.2, fair: the same colour family, but not a straight swap. Cardinal Purple is more muted, cooler than Scarlet Red.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 11). Cardinal Purple is more muted, cooler than Scarlet Red.
The same difference applies the other way round: Scarlet Red is 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 Scarlet Red on the colour wheel See Cardinal Purple on the colour wheel
All matches: Scarlet Red equivalents · Cardinal Purple equivalents