ΔE 21.7, loose: different enough that you should pick on purpose. Leather Brown is noticeably lighter, much more saturated than Kiwi Brown.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 22). Leather Brown is noticeably lighter, much more saturated than Kiwi Brown.
The same difference applies the other way round: Kiwi Brown is noticeably darker, 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 Kiwi Brown on the colour wheel See Leather Brown on the colour wheel
All matches: Kiwi Brown equivalents · Leather Brown equivalents