650 ppb to ppm

650 ppb = 0.65 ppm

ppbppm
635 ppb0.635
640 ppb0.64
645 ppb0.645
6500.65
655 ppb0.655
660 ppb0.66
665 ppb0.665

650 ppb = 0.65 ppm

Formula

1 ppm = 1 mg/L (aqueous, density ≈ 1 kg/L) · 1 ppb = 0.001 mg/L · 1% = 10,000 ppm