Convert Per mille to Parts per million
1 per mille is 1,000 ppm. One per mille is exactly 1000 parts per million.
One per mille is 1000 parts per million. To convert per mille to parts per million, multiply by 1000; to go the other way, divide by 1000 or multiply by 0.001. 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 × 1000
1 * 10001,000 ppm
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 million? The converter and the working
- 1.Take the measurement in per mille.
- 2.Multiply by 1000 — that is how many parts per million fit in one per mille.
- 3.To go back the other way, divide by 1000, or multiply by 0.001.
Worked example: 25 per mille to parts per million
- Formula
- ‰ × 1000 = ppm
- Arithmetic
- 25 × 1000 = 25,000 ppm
- Answer
- 25 ‰ = 25,000 ppm
The factor is exact, so this figure is exact too — only the display is rounded.
Per mille to parts per million conversion table
| Per mille | Parts per million |
|---|---|
| 1 ‰ | 1,000 ppm |
| 2 ‰ | 2,000 ppm |
| 3 ‰ | 3,000 ppm |
| 4 ‰ | 4,000 ppm |
| 5 ‰ | 5,000 ppm |
| 6 ‰ | 6,000 ppm |
| 7 ‰ | 7,000 ppm |
| 8 ‰ | 8,000 ppm |
| 9 ‰ | 9,000 ppm |
| 10 ‰ | 10,000 ppm |
| 12 ‰ | 12,000 ppm |
| 15 ‰ | 15,000 ppm |
| 20 ‰ | 20,000 ppm |
| 25 ‰ | 25,000 ppm |
| 50 ‰ | 50,000 ppm |
| 100 ‰ | 100,000 ppm |
| 200 ‰ | 200,000 ppm |
| 300 ‰ | 300,000 ppm |
| 500 ‰ | 500,000 ppm |
| 1000 ‰ | 1,000,000 ppm |
| 2000 ‰ | 2,000,000 ppm |
| 5000 ‰ | 5,000,000 ppm |
| 10000 ‰ | 10,000,000 ppm |
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 million?
One in a million. The working unit of drinking-water limits, CO₂ in air and dissolved solids — 1 ppm is 1 mg per liter of water, since a liter weighs a kilogram.
How many parts per million are in a per mille?
One per mille is 1000 parts per million, exactly. Going the other way, one part per million is 0.001 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 million. Rule Calculator. https://rulecalculators.com/convert/permille-to-ppm
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- "Convert Per mille to parts per million." Rule Calculator, August 16, 2026, https://rulecalculators.com/convert/permille-to-ppm.
- Chicago
- Rule Calculator. "Convert Per mille to parts per million." Rule Calculator. Last reviewed August 16, 2026. https://rulecalculators.com/convert/permille-to-ppm.
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Questions people actually ask
- How many parts per million are in a per mille?
- 1000. One in a million. The working unit of drinking-water limits, CO₂ in air and dissolved solids — 1 ppm is 1 mg per liter of water, since a liter weighs a kilogram.
- How do I convert parts per million back to per mille?
- Divide by 1000, or multiply by 0.001 — they are the same operation.
Other concentration conversions
Parts per million to per mille — the same conversion the other way.