645 g/kg to PSU

645 g/kg = 648.16 PSU

g/kgPSU
630 g/kg633.087
635 g/kg638.111
640 g/kg643.136
645648.16
650 g/kg653.185
655 g/kg658.209
660 g/kg663.234

645 g/kg = 648.16 PSU

Formula

1 g/kg ≈ 1.0049 PSU · 1 mg/L ≈ 0.001 PSU · 1 ppm ≈ 0.001 PSU (dilute aqueous approximation)