Dilution to Target PPM Calculator
Work out how much concentrated stock and how much water to combine to reach a target concentration in parts per million.
How it works
C₁V₁ = C₂V₂ · stock volume = (target ppm × final volume) ÷ stock ppm · water = final volume − stock volume
Because parts per million is a concentration, the dilution equation C₁V₁ = C₂V₂ applies directly with ppm in place of molarity. Rearranging gives the volume of concentrated stock needed; the rest of the final volume is diluent (usually water). The ratio of stock to target concentration is the dilution factor.
Worked example
To make 10 L of a 50 ppm solution from a 1000 ppm stock: stock volume = (50 × 10) ÷ 1000 = 0.5 L. Add 0.5 L of stock to 9.5 L of water — a 20× dilution.
Sources: Parts-per notation — Wikipedia
Frequently asked questions
What does ppm mean here?
Parts per million is mass per mass or mass per volume — for dilute water solutions, 1 ppm ≈ 1 mg per litre. Because it is a linear concentration, it plugs straight into the C₁V₁ = C₂V₂ dilution rule.
Why can the target not exceed the stock?
You cannot make a solution more concentrated than the stock you are diluting from. Reaching a higher ppm would require adding more solute, not diluting — so the tool flags it as an error.
Does temperature affect this?
For the small dilutions here the volume change with temperature is negligible. For very precise work, prepare and measure everything at the same temperature.
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This calculator is for educational purposes. Double-check important results before acting on them.