Convert parts per billion to parts per million
1 ppb = 0.001 ppm
1 ppb = 0.001 ppm
1 ppb in every concentration unit
| percent | 1.00e-07 % |
| fraction (0–1) | 1.00e-09 fraction |
| parts per million | 0.001 ppm |
| parts per billion | 1 ppb |
| grain per US gallon (as CaCO₃) | 0.0000584 gpg |
How the conversion works
Multiply by 0.001 to go from parts per billion to parts per million, or divide by it to go back. Every conversion on this site routes through the SI value (%) rather than a table of pairwise factors, so a round-trip returns exactly what you started with.
Going the other way? parts per million to parts per billion — 1 ppm = 1,000 ppb.
parts per billion to parts per million — common values
| 1 ppb | 0.001 ppm |
| 2 ppb | 0.002 ppm |
| 3 ppb | 0.003 ppm |
| 5 ppb | 0.005 ppm |
| 10 ppb | 0.01 ppm |
| 15 ppb | 0.015 ppm |
| 20 ppb | 0.02 ppm |
| 25 ppb | 0.025 ppm |
| 50 ppb | 0.05 ppm |
| 75 ppb | 0.075 ppm |
| 100 ppb | 0.1 ppm |
| 250 ppb | 0.25 ppm |
| 500 ppb | 0.5 ppm |
| 1000 ppb | 1 ppm |