ΔE 14.4, fair: the same colour family, but not a straight swap. Mephiston Red is more saturated, warmer than Infernal Red.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 14). Mephiston Red is more saturated, warmer than Infernal Red.
The same difference applies the other way round: Infernal Red is more muted, cooler.
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 Infernal Red on the colour wheel See Mephiston Red on the colour wheel
All matches: Infernal Red equivalents · Mephiston Red equivalents