ΔE 13.4, fair: the same colour family, but not a straight swap. Burnt Sienna is more muted, warmer than Mephiston Red.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 13). Burnt Sienna is more muted, warmer than Mephiston Red.
The same difference applies the other way round: Mephiston Red is more saturated, 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 Mephiston Red on the colour wheel See Burnt Sienna on the colour wheel
All matches: Mephiston Red equivalents · Burnt Sienna equivalents