ΔE 20.1, loose: different enough that you should pick on purpose. Khardic Flesh is a little lighter, much more muted, warmer than Poppy Red. They are different kinds of paint: Army Painter Poppy Red is a one-coat contrast-style paint and Formula P3 Khardic Flesh is an opaque base/layer paint, so they won’t behave the same on the model even where the colour is close.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 20). Khardic Flesh is a little lighter, much more muted, warmer than Poppy Red. They are different kinds of paint.
The same difference applies the other way round: Poppy Red is a little darker, much 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 Poppy Red on the colour wheel See Khardic Flesh on the colour wheel
All matches: Poppy Red equivalents · Khardic Flesh equivalents