Calculator
This mass-based tool uses ppm = (solute mass / total solution mass) × 1,000,000. Use the same mass unit for both masses.
Formula and assumptions
ppm = (solute mass / solution mass) × 10⁶
This calculator treats ppm as a mass fraction scaled by one million. Both mass entries must use the same unit.
Assumption: Both mass inputs use the same unit.
Variables and units
Worked example
1 g of solute in 999 g of solvent gives a 1,000 ppm solution by mass.
ppm, percent and mg/L
| ppm | Percent | mg per kg |
|---|---|---|
| 1 | 0.0001% | 1 mg/kg |
| 10 | 0.001% | 10 mg/kg |
| 100 | 0.01% | 100 mg/kg |
| 1,000 | 0.1% | 1,000 mg/kg |
| 10,000 | 1% | 10,000 mg/kg |
ppm on this page is mass-based: 1 ppm is 1 mg of solute per kilogram of mixture. In dilute water solutions 1 L has a mass of about 1 kg, so 1 mg/L ≈ 1 ppm; 0.5 mg of chlorine in 2 L of water is about 0.25 ppm. For gases, ppm usually means parts per million by volume (ppmv), which is a different quantity.
Important limits
Usage of ppm differs by field; this page uses a mass-based definition only.
Reference and related tools
IUPAC: parts per million. Return to Chemistry Calculators for the other tools in this group.