ΔE 11.5, fair: the same colour family, but not a straight swap. Off-White is a little darker, more saturated, warmer than J.A. Gray.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 11). Off-White is a little darker, more saturated, warmer than J.A. Gray.
The same difference applies the other way round: J.A. Gray is a little lighter, more muted, 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 J.A. Gray on the colour wheel See Off-White on the colour wheel
All matches: J.A. Gray equivalents · Off-White equivalents