Why mg per kg for ppm?

For dilute aqueous solutions, 1 kg of solution is approximately 1 liter, so mg/kg conveniently approximates mg/L — the most common way ppm is reported in water testing.

How does ppm relate to percent concentration?

1% concentration equals 10,000 ppm, since percent is parts per hundred and ppm is parts per million — ppm is used when concentrations are too small to conveniently express as a percentage.

Parts Per Million (PPM) Calculator

Calculate a solution's concentration in parts per million (ppm), a common way to express very dilute concentrations in water quality testing, environmental science, and chemistry, based on the mass of solute per mass of solution.

Inputs

Results

Concentration: 50 ppm

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Formula

ppm = Solute Mass (mg) / Solution Mass (kg)

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Solution Concentration: Five Ways to Express the Same Idea

Mass percent, molality, parts per million, percent composition, and dilution factor — five different units for describing how concentrated a solution is.

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