PPM Concentration Calculator
Convert ppm to mg/L, mg/kg, percent by mass, and molarity — or go the other direction — with optional molar mass input for molarity conversions.
Use the PPM Concentration Calculator
Concentration Input
ppm (mg/L) = ppm by volume; ppm (mg/kg) = ppm by mass
Common Solute Molar Masses
Enter a concentration on the left
Fill in the value and unit, then click Convert.
Converted Values
Key Relationships
Summary
This calculator converts parts per million (ppm) into the most common concentration units used in chemistry, environmental science, and food safety: mg/L (milligrams per liter), mg/kg (milligrams per kilogram), percent by mass (% w/w), and molarity (mol/L). For aqueous solutions at room temperature, ppm and mg/L are numerically equal because water density is approximately 1 g/mL. Enter any one unit and the rest are computed instantly in your browser — no data is sent to any server.
How it works
- Select the input unit (ppm, mg/L, mg/kg, % w/w, or molarity) from the dropdown.
- Enter the numeric concentration value in the input field.
- Enter the solution density (g/mL) — defaults to 1.00 g/mL for dilute aqueous solutions.
- Optionally enter the solute molar mass (g/mol) to enable molarity conversion.
- Click Convert to see all equivalent concentration values instantly.
- Click any result to copy it, or use Copy All to grab all values at once.
Use cases
- Convert drinking-water contaminant limits from ppm to mg/L for regulatory compliance.
- Check nutrient solution concentrations in hydroponics or aquaculture.
- Convert food additive limits between ppm, mg/kg, and percent by mass.
- Calculate molarity from a ppm reading in environmental water quality reports.
- Cross-check reagent concentrations in analytical chemistry protocols.
- Convert soil contamination data between mg/kg and percent by mass.
- Prepare standard solutions for calibration by working backward from target ppm.
- Verify concentration consistency between lab instruments reporting different units.