ppm and ppt are defined as:
1ppm = 1/106 = 10-6
1ppt = 1/1012 = 10-12
So
1ppm = 106ppt
The number of parts-per million xppm is equal to the number of parts-per trillion xppt divided by 106:
xppm = xppt / 106
Example: 7000ppt is equal to 0.007000ppm:
xppt = 7000ppt / 106 = 0.007ppm
| ppt | ppm |
|---|---|
| 1 | 0.000001 |
| 10 | 0.00001 |
| 100 | 0.0001 |
| 1000 | 0.001 |
| 10000 | 0.01 |
| 100000 | 0.1 |
| 106 | 1 |
| 107 | 10 |
| 108 | 100 |
| 109 | 1000 |
| 1010 | 10000 |