Parts Per Million Calculator
Convert between parts per million (ppm) and other ratio units — percent, ppb, and ppt.
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- Accurate results
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- Works on all devices
Enter a ratio value and choose a from/to unit to convert between ppm, percent, ppb, and ppt.
Your result
0
Converted value
Equivalent in water (mg/L)1
AI explanation
Formula
Converted value = amount × (from-unit-to-fraction factor) ÷ (to-unit-to-fraction factor)Worked example
1 ppm to percent
| Field | Value |
|---|---|
| Amount | 1 |
| From unit | ppm |
| To unit | % |
| Converted value | 0.0001 |
| Equivalent in water (mg/L) | 1 |
Assumptions
- The "equivalent in water" figure assumes a dilute aqueous solution (density ≈1000 g/L), where 1 ppm by mass is very close to 1 mg/L — a standard approximation in water-quality contexts, but not exact for other solvents or concentrated solutions.
Frequently asked questions
What does 1 ppm mean?
1 part per million means 1 unit of something in a total of 1 million units — equivalent to 0.0001%, or (in a dilute aqueous solution) approximately 1 milligram per liter.
Where are ppm values commonly used?
Water quality testing (contaminant levels), air quality (pollutant concentrations), and trace chemical concentrations in manufacturing are common contexts for ppm.
I need parts per billion instead — is there a dedicated version?
Yes — see the Parts Per Billion Calculator, which uses the same conversion with ppb as the default unit.