ΔE 13.7, fair: the same colour family, but not a straight swap. Scarlet Red is more saturated, cooler than Burnt Sienna.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 14). Scarlet Red is more saturated, cooler than Burnt Sienna.
The same difference applies the other way round: Burnt Sienna is more muted, 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 Burnt Sienna on the colour wheel See Scarlet Red on the colour wheel
All matches: Burnt Sienna equivalents · Scarlet Red equivalents