What this calculator does
PPM to molarity works out converts a concentration in ppm (mg/L) to molarity using the solute molar mass. Enter your own figures above and the answer updates as you type: nothing is fixed in the code, so the result reflects exactly the numbers you supply.
The formula this calculator evaluates is printed under the tool and explained below, so you can check the working by hand or reuse it in a spreadsheet.
The formula
FormulaM = ppm ÷ (1000 × molar mass), assuming a dilute aqueous solution where 1 ppm ≈ 1 mg/L
The inputs explained
| Field | What to enter |
|---|---|
| Concentration (ppm) | A number, measured in ppm. Starts at 100. |
| Molar mass (g/mol) | A number, measured in g/mol. Starts at 58.44. |
Worked examples
Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.
How the answer changes with concentration
Every other input is held at the calculator’s starting values while concentration varies. Select any row to load that scenario into the calculator.
How the answer changes with concentration
| Concentration (ppm) | Molarity | Concentration used | Molar mass used |
|---|---|---|---|
| 50 | 0.00085558 mol/L | 50.00 ppm (mg/L) | 58.44 g/mol |
| 75 | 0.00128337 mol/L | 75.00 ppm (mg/L) | 58.44 g/mol |
| 100 | 0.00171116 mol/L | 100.00 ppm (mg/L) | 58.44 g/mol |
| 150 | 0.00256674 mol/L | 150.00 ppm (mg/L) | 58.44 g/mol |
| 200 | 0.00342231 mol/L | 200.00 ppm (mg/L) | 58.44 g/mol |
| 300 | 0.00513347 mol/L | 300.00 ppm (mg/L) | 58.44 g/mol |