ΔE 17.7, loose: different enough that you should pick on purpose. Estus Yellow is a little lighter, much more muted than Bad Moon Yellow.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 18). Estus Yellow is a little lighter, much more muted than Bad Moon Yellow.
The same difference applies the other way round: Bad Moon Yellow is a little darker, much more saturated.
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 Bad Moon Yellow on the colour wheel See Estus Yellow on the colour wheel
All matches: Bad Moon Yellow equivalents · Estus Yellow equivalents