How to use this calculator
- Select the ppm basis or conversion mode.
- Enter the solute value and the total solution value on the same basis.
- Enter density only for a density-based mass-volume conversion.
- Calculate and read the basis shown with the result.
Formula and variables
ppm = mass fraction × 10⁶
| Symbol | Meaning | Unit |
|---|---|---|
| ppm | parts per million | 10⁻⁶ mass fraction |
| ρ | density | kg/L |
Worked example
10 ppm by mass is 12 mg/L at a measured density of 1.2 kg/L. It is approximately 10 mg/L for a water-like density.
Interpretation
The output labels whether it is a mass fraction or mass-per-volume value and discloses every density assumption.
Common mistakes
- Do not treat ppm and mg/L as universally equal.
- Use matching mass units for mass/mass mode.
Frequently asked questions
Is 1 ppm always equal to 1 mg/L?
No. That equality needs a water-like density or an explicit mass-volume definition.
Which ppm bases are supported?
The tool supports mass, volume, mole, mass-volume, percent, ppb, and density-aware modes.
How do I convert percent to ppm?
Multiply percent by 10,000. One percent equals 10,000 ppm.
Can I use scientific notation?
Yes. Enter values such as 6.022e23 or 1.0e-6 in a numeric field.
How should I round the result?
Keep extra digits during the calculation. Round the final result to the precision required by your data.