ΔE 7.8, close: similar, with a visible difference side by side. IAF Sand is a little darker, cooler than Sand FS 33531.
✓ AK 3rd Generation equivalence chart lists these two as equivalents.
Usually, if you are not matching paint already on the model. Close match (ΔE 8). IAF Sand is a little darker, cooler than Sand FS 33531.
The same difference applies the other way round: Sand FS 33531 is a little lighter, 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 Sand FS 33531 on the colour wheel See IAF Sand on the colour wheel
All matches: Sand FS 33531 equivalents · IAF Sand equivalents