🧪 PPM Calculator
Convert a concentration between parts per million (ppm), percent, and milligrams per liter (mg/L) for dilute aqueous solutions.
What is PPM?
Parts per million (ppm) is a way of expressing very small, dilute concentrations — one part of a substance per one million parts of the whole solution or mixture. It is widely used in water quality testing, chemistry, and environmental science.
How the Conversion Works
Since 1 ppm equals 0.0001%, converting between ppm and percent is a matter of dividing or multiplying by 10,000. For dilute water-based solutions, 1 ppm is also conveniently approximated as 1 milligram of solute per liter of water (mg/L), because 1 liter of water weighs almost exactly 1,000,000 milligrams.
- ppm = percent × 10,000
- ppm ≈ mg/L (for dilute aqueous solutions)
This tool is intended for general educational and planning purposes; for regulated water testing or lab reporting, follow your accredited lab’s exact methodology.