Case 1
- Mass of solute (g)
- 0.005g
- Mass of the whole solution (g)
- 1000g
5.000ppm
Open with these valuesPPM Calculator
5.000ppm
Result: 5.000 ppmParts per million by mass: divide the solute mass by the mass of the whole solution and multiply by a million. 0.005 g in 1000 g of solution is 5 ppm. Both masses must use the same unit — the ratio cancels them — and one percent is exactly 10,000 ppm.
Worked examples
Case 2
- Mass of solute (g)
- 1g
- Mass of the whole solution (g)
- 1000g
1,000.000ppm
Open with these valuesCase 3
- Mass of solute (g)
- 2.5g
- Mass of the whole solution (g)
- 500g
5,000.000ppm
Open with these valuesHow it's calculated
ppm = (mass of solute ÷ mass of solution) × 1,000,000
- StepWeigh the dissolved substance.
- StepWeigh the whole solution, solute included, in the same unit.
- ResultDivide the first by the second and multiply by one million.
Reference table
| Solute, solution | Same figure as a percentage | In ppm |
|---|---|---|
| 0.5, 1000000 | 0.00005 % | 0.500 |
| 0.005, 1000 | 0.0005 % | 5.000 |
| 0.001, 100 | 0.001 % | 10.000 |
| 1, 1000 | 0.1 % | 1000.000 |
| 2.5, 500 | 0.5 % | 5000.000 |
Questions
How do I calculate ppm?
Divide the mass of the solute by the mass of the whole solution and multiply by one million. 0.005 g of a substance in 1000 g of solution gives 5 ppm.
Is this ppm by mass or by volume?
By mass — both inputs are masses, which is the usual reading in water and food chemistry. A volume-based ppm differs by the density of the mixture, so do not mix the two conventions.
How do I convert ppm to a percentage?
Divide by 10,000, because one percent is 10,000 ppm. So 5 ppm is 0.0005 %, and 1000 ppm is 0.1 %.
Is 1 ppm the same as 1 mg per litre?
For dilute water solutions, near enough. One litre of water weighs about a million milligrams, so 1 mg per litre works out at roughly 1 ppm by mass. The shortcut breaks down once the solution is far from the density of water.
Which units should I use for the two masses?
The same one for both — grams and grams, or kilograms and kilograms. The mass of the solution includes the solute, because it is the total mass of the mixture.
Sources and last check
Information, not professional advice.