ΔE 21.0, loose: different enough that you should pick on purpose. Copper is a little darker, cooler than Viking Gold.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 21). Copper is a little darker, cooler than Viking Gold.
The same difference applies the other way round: Viking Gold 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 Viking Gold on the colour wheel See Copper on the colour wheel
All matches: Viking Gold equivalents · Copper equivalents