ΔE 14.2, fair: the same colour family, but not a straight swap. Indigo is a little lighter, much more muted, warmer than Gothic Blue.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 14). Indigo is a little lighter, much more muted, warmer than Gothic Blue.
The same difference applies the other way round: Gothic Blue 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 Gothic Blue on the colour wheel See Indigo on the colour wheel
All matches: Gothic Blue equivalents · Indigo equivalents