From To A mA uA kA
A 1 1000 1e+06 0.001
mA 0.001 1 1000 1e-06
uA 1e-06 0.001 1 0
kA 1000 1e+06 1e+09 1

Each cell shows the factor to convert 1 unit of the row header into the column header.

Highlighted diagonal cells represent identity conversions (1:1).