When to use this calculator
Specify whether ppm is a mass or volume ratio; this tool uses mass in both numerator and denominator.
Explore the concentration & mixtures calculators for other questions in this topic. For a related calculation, use the Serial Dilution Concentration Calculator: Estimate concentration after equal serial dilution stages.
PUTTING IT INTO PRACTICE
Parts Per Million: a worked example
The values below are an illustrative example, not a recommendation. Replace them with measurements or assumptions that match your question.
| Input | Example value |
|---|---|
| Solute mass (mg) | 5 |
| Total mixture mass (kg) | 2 |
| Result | 2.5 ppm by mass |
- Check the input labels and enter the example values above.
- Apply the relationship: Mass ppm = solute mass(mg)/mixture mass(kg).
- The result is 2.5 ppm by mass, rounded for display.
How to interpret your result
Mass ppm equals mg/kg. It only approximates mg/L when solution density is close to 1 kg/L.
Keep mass, amount and volume definitions separate. Molarity uses final solution volume; molality uses solvent mass. A dilution cannot increase concentration without some process beyond adding solvent.
Frequently asked questions
Are molarity and molality interchangeable?
No. Molarity is amount per solution volume, while molality is amount per solvent mass.
When is the parts per million calculator useful?
Specify whether ppm is a mass or volume ratio; this tool uses mass in both numerator and denominator.
How do I use the parts per million calculator?
Enter solute mass (mg), total mixture mass (kg). The result updates automatically. Use the units shown beside each input; the example values illustrate the method.
Which formula does this calculator use?
Mass ppm = solute mass(mg)/mixture mass(kg).
What should I check before using the result?
Mass ppm equals mg/kg. It only approximates mg/L when solution density is close to 1 kg/L.
How are results rounded?
Scalar numbers display up to six decimal places, with scientific notation for very large or small values. Text, fraction, date and schedule outputs use the format described on the tool. Intermediate calculations use JavaScript floating-point arithmetic. Keep sensible precision for your measurements.
Further reading
For background on this topic, see OpenStax: molarity and dilution ↗. This is a topic reference, not an external review or endorsement of this tool.
Calculators Map editorial process · Updated · Methods and limitations