PPM Calculator
Convert between parts-per-million and mass of solute / solution
What do you know?
1 ppm = 1 part solute per 1,000,000 parts solution (≈ mg/L for dilute aqueous solutions).
For dilute aqueous solutions, 1 mL ≈ 1 g.
Result:
Quick Reminders
- For water-based solutions, ppm ≈ mg of solute per liter of solution.
- Always use the same units for solute and solution mass before taking the ratio.
- For gases, ppm often refers to volumes; this tool assumes masses/liquids.
How parts per million are calculated
Formula
ppm = part / whole × 1,000,000
PPM expresses a very small ratio. For dilute water solutions, 1 mg/L is approximately 1 ppm when density is near 1 kg/L.
Worked example
Five milligrams of solute in one liter of dilute water is approximately 5 ppm.
Common mistake
The mg/L shortcut depends on solution density and is not exact for every liquid.