650.5 ppb to ppm

650.5 ppb = 0.65 ppm

ppbppm
635.5 ppb0.636
640.5 ppb0.64
645.5 ppb0.645
650.50.65
655.5 ppb0.655
660.5 ppb0.66
665.5 ppb0.665

650.5 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