mg/L to ppm Calculator
Enter concentration and final solution density at the same temperature; the density is required.
Formula
ppm = concentration (mg/L) ÷ density (kg/L); 1 g/cm³ = 1 kg/L.
Solute mass concentration: 120 mg/L · Final solution density (required): 1.2 g/cm³ · Mass fraction in ppm (mg/kg) ≈ (120 mg/L × 0.001 kg/m³/mg/L)÷(1.2 g/cm³ × 1,000 kg/m³/g/cm³)×1000000 · Mass fraction as percent ≈ (100)÷10000
How to use
- Enter the solute concentration.
- Replace the example density with your final solution density.
- Read ppm as mg of solute per kg of solution.
Examples
- 120 mg/L at 1.2 g/cm³ equals 100 mg/kg = 100 ppm.
Frequently asked questions
Is 1 mg/L always 1 ppm?
Only when density is 1 kg/L. The default 1.2 g/cm³ is an editable example, not a water assumption.
Which density is needed?
Use the final solution, not pure solvent or solute. This computes mass fraction, not gas volume or mole ppm.
What is the supported range?
Concentration: 0–100,000 mg/L. Density: 0.1–25 g/cm³. These bounds keep the mass fraction at most 1.
Sources
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