PPM Converter (Parts Per Million)
Convert between parts per million (ppm) and other concentration units including percentage, milligrams per liter, and milligrams per kilogram. Essential for water quality testing, chemistry, environmental science, and industrial applications.
Parts per million (ppm) is a dimensionless measure of concentration. It represents one part of a substance per one million parts of the total. PPM is widely used in water quality testing, air pollution monitoring, and chemical analysis.
Key conversion relationships:
- 1 ppm = 0.0001% (1 part in 10,000 of a percent)
- 1% = 10,000 ppm
- 1 ppm ≈ 1 mg/L (for dilute aqueous solutions at ~1 g/mL density)
- 1 ppm = 1 mg/kg (by mass definition)
- 1 mg/L = 1 μg/mL
Common PPM Reference Values:
| Application | Typical PPM | Equivalent % |
|---|---|---|
| Drinking water chlorine | 0.2–4 ppm | 0.00002–0.0004% |
| Pool chlorine | 1–3 ppm | 0.0001–0.0003% |
| CO₂ in atmosphere | ~420 ppm | 0.042% |
| Alcohol in blood (legal limit) | ~800 ppm | 0.08% |
| Salt in seawater | ~35,000 ppm | 3.5% |
The approximation that 1 ppm equals 1 mg/L holds true for dilute aqueous solutions where the density is close to 1 g/mL (like water). For denser or non-aqueous solutions, a density correction factor must be applied.