ΔE 11.4, fair: the same colour family, but not a straight swap. Beige is a little lighter, more saturated than Buff.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 11). Beige is a little lighter, more saturated than Buff.
The same difference applies the other way round: Buff is a little darker, more muted.
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 Buff on the colour wheel See Beige on the colour wheel
All matches: Buff equivalents · Beige equivalents