Convert Per mille to Parts per trillion
1 per mille is 1,000,000,000 ppt. One per mille is exactly 1000000000 parts per trillion.
One per mille is 1000000000 parts per trillion. To convert per mille to parts per trillion, multiply by 1000000000; to go the other way, divide by 1000000000 or multiply by 1.0000 × 10^-9. The factor is exact rather than rounded: it follows from NIST SP 811 §7.10.3. Parts per thousand, written ‰.
Factor checked against the defining standard · How we check
- Per mille × 1000000000
1 * 10000000001,000,000,000 ppt
1 per mille in every concentration unit
| Unit | Value | Exact factor |
|---|---|---|
| per cent | 0.1 % | × 0.1 |
| per mille (as entered) | 1 ‰ | — |
| parts per million | 1,000 ppm | × 1,000 |
| parts per billion | 1,000,000 ppb | × 1,000,000 |
| parts per trillion | 1,000,000,000 ppt | × 1,000,000,000 |
Factors are entered by hand from NIST SP 811 §7.10.3 rather than derived from a units library, so the ones that terminate are exact rather than rounded.
How do you convert per mille to parts per trillion? The converter and the working
- 1.Take the measurement in per mille.
- 2.Multiply by 1000000000 — that is how many parts per trillion fit in one per mille.
- 3.To go back the other way, divide by 1000000000, or multiply by 1.0000 × 10^-9.
Worked example: 25 per mille to parts per trillion
- Formula
- ‰ × 1000000000 = ppt
- Arithmetic
- 25 × 1000000000 = 25,000,000,000 ppt
- Answer
- 25 ‰ = 25,000,000,000 ppt
The factor is exact, so this figure is exact too — only the display is rounded.
Per mille to parts per trillion conversion table
| Per mille | Parts per trillion |
|---|---|
| 1 ‰ | 1,000,000,000 ppt |
| 2 ‰ | 2,000,000,000 ppt |
| 3 ‰ | 3,000,000,000 ppt |
| 4 ‰ | 4,000,000,000 ppt |
| 5 ‰ | 5,000,000,000 ppt |
| 6 ‰ | 6,000,000,000 ppt |
| 7 ‰ | 7,000,000,000 ppt |
| 8 ‰ | 8,000,000,000 ppt |
| 9 ‰ | 9,000,000,000 ppt |
| 10 ‰ | 10,000,000,000 ppt |
| 12 ‰ | 12,000,000,000 ppt |
| 15 ‰ | 15,000,000,000 ppt |
| 20 ‰ | 20,000,000,000 ppt |
| 25 ‰ | 25,000,000,000 ppt |
| 50 ‰ | 50,000,000,000 ppt |
| 100 ‰ | 100,000,000,000 ppt |
| 200 ‰ | 200,000,000,000 ppt |
| 300 ‰ | 300,000,000,000 ppt |
| 500 ‰ | 500,000,000,000 ppt |
| 1000 ‰ | 1,000,000,000,000 ppt |
| 2000 ‰ | 2,000,000,000,000 ppt |
| 5000 ‰ | 5,000,000,000,000 ppt |
| 10000 ‰ | 10,000,000,000,000 ppt |
What is a per mille?
Parts per thousand, written ‰. Used for blood alcohol in most of Europe, for salinity, and for slope in rail engineering.
What is a part per trillion?
One in a million million. PFAS limits are set here — the EPA’s 2024 drinking-water rule is 4 ppt, which is four drops in a thousand Olympic pools.
How many parts per trillion are in a per mille?
One per mille is 1000000000 parts per trillion, exactly. Going the other way, one part per trillion is 1.0000 × 10^-9 per mille. Both figures come from the same defined relation rather than from a measurement, which is why they are the same today as they were in 1959.
Every concentration unit here
The whole group — 5 units with their symbols and the size of each one in part per millions — is on the conversion index, along with every pair it makes. The table above already gives each of them relative to a per mille.
Source: NIST SP 811 §7.10.3 — why ppm, ppb and ppt should be avoided and what they mean
Cite this page
- APA
- Rule Calculator. (2026). Convert Per mille to parts per trillion. Rule Calculator. https://rulecalculators.com/convert/permille-to-ppt
- MLA
- "Convert Per mille to parts per trillion." Rule Calculator, August 16, 2026, https://rulecalculators.com/convert/permille-to-ppt.
- Chicago
- Rule Calculator. "Convert Per mille to parts per trillion." Rule Calculator. Last reviewed August 16, 2026. https://rulecalculators.com/convert/permille-to-ppt.
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Questions people actually ask
- How many parts per trillion are in a per mille?
- 1000000000. One in a million million. PFAS limits are set here — the EPA’s 2024 drinking-water rule is 4 ppt, which is four drops in a thousand Olympic pools.
- How do I convert parts per trillion back to per mille?
- Divide by 1000000000, or multiply by 1.0000 × 10^-9 — they are the same operation.
Other concentration conversions
Parts per trillion to per mille — the same conversion the other way.