ΔE 11.9, fair: the same colour family, but not a straight swap. Buff is a little lighter, more saturated, cooler than Sandy Tan.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 12). Buff is a little lighter, more saturated, cooler than Sandy Tan.
The same difference applies the other way round: Sandy Tan is a little darker, 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 Sandy Tan on the colour wheel See Buff on the colour wheel
All matches: Sandy Tan equivalents · Buff equivalents