PPM and Concentration Converter
Convert a concentration between common units for water-like solutions.
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PPM and Concentration Converter by TheCalcTools
How the PPM and Concentration Converter works
Enter the mass of solute in milligrams, the volume in litres and (optionally) the molar mass.
For dilute aqueous solutions, 1 ppm is 1 mg per litre because water has a density of about 1 kg/L.
Percent concentration and molarity follow from the same figures.
The formula
Worked example
Using the default values shown in the calculator:
| Solute mass (mg) | 250 |
|---|---|
| Solution volume (L) | 1 |
| Molar mass (g/mol, optional) | 58.44 |
- 250 mg in 1 L is 250 ppm.
- That equals 0.0250% w/v, or 250,000 ppb.
- With a molar mass of 58.44 the molarity is 4.278 mmol/L.
Result:
| ppm (mg/L) | 250.00 |
|---|---|
| Percent (w/v) | 0.0250 |
| ppb (µg/L) | 250,000 |
| Molarity (mmol/L) | 4.278 |
Frequently asked questions
Is ppm always mg/L?
Only for dilute water-based solutions. For other media ppm means parts per million by mass or volume, so check the context.
What is ppb?
Parts per billion, which is 1 µg per litre in water.
Sources and further reading
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This calculator gives estimates for information only. Check important results independently before you rely on them. See our disclaimer.