🧴 PPM Calculator (Parts Per Million)
Convert between mass and parts-per-million concentration: ppm = (mass solute ÷ mass solution) × 10⁶.
Concentration
5 ppm
ppm = (mass of solute ÷ mass of solution) × 10⁶. Use the same mass unit for both. For dilute water, 1 ppm ≈ 1 mg/L. 🔒 Computed in your browser.
How the ppm calculator (parts per million) works
Parts per million is a mass fraction scaled by a million: ppm = (mass of solute ÷ mass of solution) × 10⁶, with both masses in the same unit. Enter any two of solute mass, solution mass and ppm and the tool solves for the third. For dilute aqueous solutions, 1 ppm ≈ 1 mg/L. The same scaling extends to related units: 1 ppm = 10⁻⁴ %, 1000 ppb, and, for dilute water, about 1 mg/L or 1 µg/mL.
The standard way to express trace concentrations, water hardness, pollutants, additives. 1 ppm is one part in a million: 1 mg in 1 kg, or roughly 1 mg per litre of water.
Frequently asked questions
How do I calculate ppm?
Divide the mass of solute by the mass of solution and multiply by 1,000,000. 5 mg of solute in 1000 g of solution = (0.005/1000) × 10⁶ = 5 ppm.
Is 1 ppm the same as 1 mg/L?
For dilute water-based solutions, yes, because 1 L of water weighs about 1 kg, 1 mg/L ≈ 1 ppm. For other solvents or concentrated solutions, use the mass definition.
How do I convert ppm to a percentage?
1% = 10,000 ppm, so divide ppm by 10,000. 250 ppm = 0.025%.
What is ppb?
Parts per billion, the same idea scaled by 10⁹ instead of 10⁶. 1 ppm = 1000 ppb.
What is ppm used for?
Expressing very low concentrations: water hardness, dissolved oxygen, CO₂ levels, contaminants and food additives are all commonly given in ppm.
How many grams of solute are in 2 L of a 50 ppm solution?
For dilute water, 50 ppm ≈ 50 mg/L, so 2 L holds 100 mg = 0.1 g. For non-aqueous or concentrated solutions, use the mass definition with the actual solution mass.
How do I convert a percentage to ppm?
Multiply the percent by 10,000, since 1% = 10,000 ppm. A 0.0025% solution is 25 ppm.