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Mass-Fraction ppm to Molarity at 1 kg/L

Convert mass-based parts per million or billion to molarity at the fixed solution-density assumption of 1 kg/L.

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A solution containing 100 ppm by mass, with density 1 g/mL and solute molar mass 50 g/mol, has concentration 0.002 mol/L.

Molarity in mol/L = mass-based ppm × density in g/mL / (1000 × molar mass in g/mol)

Enter these known values and leave the other values blank.

All quantities are positive. Here ppm means milligrams of solute per kilogram of solution; ppb means micrograms per kilogram.
This retained mode fixes solution density at 1 g/mL, equal to 1 kg/L. This mode is unsuitable when a different density is required.
These mass fractions are different from gas-volume ppm or mole-fraction ppm. A density of 1 g/mL is a fixed assumption here, not a universal property of aqueous solutions.

No. Mass-based ppm equals mg/kg. It has the same numerical value as mg/L only when solution density is 1 kg/L.

No. Gas-volume and mole fractions need a different conversion based on the specified gas state and fraction definition.

Bookify uses exact customary mass and volume definitions for density units, replacing rounded factors in the reference.