Convert Parts per billion to Per cent
1 part per billion is 1.00e-7 %. One part per billion is exactly 1e-7 per cent.
One part per billion is 1.0000 × 10^-7 per cent. To convert parts per billion to per cent, multiply by 1.0000 × 10^-7; to go the other way, divide by 1.0000 × 10^-7 or multiply by 10000000. The relation is exact but the figure is not: it is a rounding of a number that does not terminate, and it follows from NIST SP 811 §7.10.3. One in a thousand million, on the short scale.
Factor checked against the defining standard · How we check
- Parts per billion × 1.0000 × 10^-7
1 * 0.00000010 %
1 part per billion in every concentration unit
| Unit | Value | Exact factor |
|---|---|---|
| per cent | 0.0000001 % | × 0.0000001 |
| per mille | 0.000001 ‰ | × 0.000001 |
| parts per million | 0.001 ppm | × 0.001 |
| parts per billion (as entered) | 1 ppb | — |
| parts per trillion | 1,000 ppt | × 1,000 |
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 parts per billion to per cent? The converter and the working
- 1.Take the measurement in parts per billion.
- 2.Multiply by 1.0000 × 10^-7 — that is how many per cent fit in one part per billion.
- 3.To go back the other way, divide by 1.0000 × 10^-7, or multiply by 10000000.
Worked example: 25 parts per billion to per cent
- Formula
- ppb × 1.0000 × 10^-7 = %
- Arithmetic
- 25 × 1.0000 × 10^-7 = 0.0000025 %
- Answer
- 25 ppb = 0.0000025 %
The factor is rounded for display; the figure above is computed from the full value.
Parts per billion to per cent conversion table
| Parts per billion | Per cent |
|---|---|
| 1 ppb | 1.00e-7 % |
| 2 ppb | 2.00e-7 % |
| 3 ppb | 3.00e-7 % |
| 4 ppb | 4.00e-7 % |
| 5 ppb | 5.00e-7 % |
| 6 ppb | 6.00e-7 % |
| 7 ppb | 7.00e-7 % |
| 8 ppb | 8.00e-7 % |
| 9 ppb | 9.00e-7 % |
| 10 ppb | 0.000001 % |
| 12 ppb | 0.0000012 % |
| 15 ppb | 0.0000015 % |
| 20 ppb | 0.000002 % |
| 25 ppb | 0.0000025 % |
| 50 ppb | 0.000005 % |
| 100 ppb | 0.00001 % |
| 200 ppb | 0.00002 % |
| 300 ppb | 0.00003 % |
| 500 ppb | 0.00005 % |
| 1000 ppb | 0.0001 % |
| 2000 ppb | 0.0002 % |
| 5000 ppb | 0.0005 % |
| 10000 ppb | 0.001 % |
What is a part per billion?
One in a thousand million, on the short scale. The EPA states lead and arsenic limits in it, and the ambiguity of "billion" is exactly why NIST asks for 10⁻⁹ instead.
What is a per cent?
Parts per hundred. One per cent is 10,000 ppm, which is the conversion people reach for when a water report and a lab result are in different units.
How many per cent are in a part per billion?
One part per billion is 1.0000 × 10^-7 per cent. Going the other way, one per cent is 10000000 parts per billion. 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 part per billion.
Source: NIST SP 811 §7.10.3 — why ppm, ppb and ppt should be avoided and what they mean
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Questions people actually ask
- How many per cent are in a part per billion?
- 1.0000 × 10^-7. Parts per hundred. One per cent is 10,000 ppm, which is the conversion people reach for when a water report and a lab result are in different units.
- How do I convert per cent back to parts per billion?
- Divide by 1.0000 × 10^-7, or multiply by 10000000 — they are the same operation.
Other concentration conversions
Per cent to parts per billion — the same conversion the other way.