It'll take all four tyres from 20psi to 40psi in about 60 seconds or so. With a larger compressor it'll be faster, but I need my compressor to be portable so reasonably compact.
There's loads of cheap compressors here as well, but serious four wheelers won't use them because they're slow and unreliable; they often heat up so much they fail, and need to be cooled in between tyres.