PPB to Parts per Trillion Converter
Common Conversions
| ppb | ppt |
|---|---|
| 0.001 | 1 |
| 0.005 | 5 |
| 0.01 | 10 |
| 0.05 | 50 |
| 0.1 | 100 |
| 0.5 | 500 |
| 1 | 1000 |
| 5 | 5000 |
| 10 | 10000 |
| 100 | 100000 |
| 1000 | 1000000 |
| 10000 | 10000000 |
Why this conversion matters in chemistry
PFAS regulatory work hits this regularly. The 2024 EPA primary MCL for PFOA in drinking water is 4 ppt — three orders of magnitude tighter than the older 70 ppt PFOS+PFOA non-mandatory health advisory issued in 2016. Bridging pre-2020 ppb-scale literature against current ppt-scale regulatory thresholds is the usual first step in any drinking-water monitoring compliance assessment under the Safe Drinking Water Act. Where the 1000 ppt per ppb comes from: the prefix difference between billion and trillion.
Formula
ppt = ppb × 1000
Worked Examples
1 ppb = 1000 ppt
The conversion anchor — the prefix step from billion to trillion.
0.1 ppb = 100 ppt
About a sub-ppb working concentration in ppt.
0.001 ppb = 1 ppt
A single ppt — about the modern PFOA MCL scale.
10 ppb = 10000 ppt
10 ppb — about a typical heavy-metal MCL in ppt form.
Frequently Asked Questions
How do I convert ppb to ppt?
Multiply by 1000. So 0.5 ppb becomes 500 ppt. The relationship is exact through the prefix difference.
Why use ppt instead of ppb?
Sub-ppb concentrations land in cleaner numerical form when expressed in ppt. 0.05 ppb is awkward to read; 50 ppt is concrete. The ppt form keeps the trace-level numbers in a single- to double-digit range.
What's the full prefix scale?
% > ppm > ppb > ppt > ppq. Each step scales by 1000 going down (or ÷1000 going up). The chain extends through ppq (parts per quadrillion) for the lowest detection regimes.