Select molarity, mass concentration, or implied molar mass and enter the two known values. Presets set molar mass; density converts between ppm by mass (mg/kg) and mg/L.

ppm by mass means mg/kg. mg/L and g/m³ are mass per volume. Density defaults to 1 kg/L (1 g/mL); change it for other solutions. Changing basis reinterprets the entered number.

Solution density · blank = 1 kg/L

Blank uses 1 kg/L. Enter measured solution density at the relevant temperature.

Calculator Operations Required Inputs
Convert Molarity and Molar Mass to PPM Molarity, Molar Mass
Convert PPM and Molar Mass to Molarity PPM, Molar Mass
Convert PPM and Molarity to Molar Mass PPM, Molarity

PPM to Molarity Formula

For ppm by mass (mg/kg), use solution density ρ in kg/L. For mg/L concentration, omit ρ from the following equation.

M = (PPM × ρ) / (mm × 1000)
  • M is the molarity (mol/L)
  • mm is the molar mass (g/mol)
  • PPM is the solute mass concentration in mg/kg; ρ is solution density in kg/L (numerically equal to g/mL).

Multiply mass-basis ppm by solution density in kg/L, then divide by molar mass in g/mol and by 1000. For a dilute aqueous solution at approximately 1 kg/L, ppm is approximately equal to mg/L. Use the molar mass of the same compound, ion, or element as the reported solute mass. Preset molar masses are conventional approximate values; verify hydration and reporting basis.

PPM (mg/L) to Molarity Conversion Table — Sodium chloride (NaCl), MW = 58.443 g/mol; aqueous basis (ρ = 1.000 g/mL)
PPM (mg/L) Molarity (mmol/L)
0.10.002
0.50.009
10.017
20.034
50.086
100.171
250.428
500.856
751.283
1001.711
1502.567
2003.422
2504.278
3005.133
4006.844
5008.555
75012.833
100017.111
150025.666
200034.221
* Rounded to 3 decimals. Assumes NaCl (MW = 58.443 g/mol). For aqueous mg/L: mmol/L ≈ ppm ÷ 58.443; mol/L = mmol/L ÷ 1000.

PPM to Molarity Conversion

The conversion of PPM to molarity involves using the molar mass along with the equation above to calculate molarity.

PPM to Molarity Example

How to convert PPM to molarity?

  1. First, determine the PPM.

    Calculate the total parts per million of the solution or substance.

  2. Next, determine the molar mass.

    Measure or calculate the molar mass in g/mol.

  3. Finally, calculate the molarity.

    Calculate the molarity with the equation above.

FAQ

What is molar mass?

Molar mass is a measure of the total mass per mol of substance.