ΔE 23.0, loose: different enough that you should pick on purpose. German Yellow is a little darker, much more saturated than Hammerfall Khaki.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 23). German Yellow is a little darker, much more saturated than Hammerfall Khaki.
The same difference applies the other way round: Hammerfall Khaki is a little lighter, much 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 Hammerfall Khaki on the colour wheel See German Yellow on the colour wheel
All matches: Hammerfall Khaki equivalents · German Yellow equivalents