ΔE 13.3, fair: the same colour family, but not a straight swap. Blue is noticeably lighter, more saturated than Ultramarine Blue.
✓ Herrick Games paint comparison chart lists these two as equivalents.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 13). Blue is noticeably lighter, more saturated than Ultramarine Blue.
The same difference applies the other way round: Ultramarine Blue is noticeably 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 Ultramarine Blue on the colour wheel See Blue on the colour wheel
All matches: Ultramarine Blue equivalents · Blue equivalents