15 ppb to ppm

15 ppb = 0.015 ppm

ppbppm
12 ppb0.012
13 ppb0.013
14 ppb0.014
150.015
16 ppb0.016
17 ppb0.017
18 ppb0.018

15 ppb = 0.015 ppm

Formula

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