Convert ppm to mg/L, percent and ppb — plus a C1V1 = C2V2 dilution calculator.
PPM Converter result
For water-like liquids (density ≈ 1 kg/L), 1 ppm ≈ 1 mg/L. For other liquids or gases, ppm is a ratio, not a mass concentration — the mg/L equivalence only holds at density 1.
How to use this tool
Type the value, for example 100.
Choose ppm, mg/L, percent, ppb or µg/L.
All units appear together for cross-checking.
Enter C1, C2 and final volume V2 for the stock volume V1.
Formula & worked example
100 ppm = 100 mg/L in water = 0.01% = 100,000 ppb. Dilution: to make 10 litres at 100 ppm from 1,000 ppm stock, use 1 litre of stock (100 × 10 ÷ 1,000).
Limitations — read this before you rely on it
The ppm = mg/L equivalence assumes a water-like density of 1 kg/L. For gases, ppm is normally a volume ratio and mass conversion needs molar mass and conditions.
Frequently asked questions
In water, yes — because 1 litre of water weighs about 1 kg, so 1 mg per kg is 1 mg per litre. In other liquids it depends on density.
10,000 ppm. One percent is one part in a hundred; ppm is parts in a million.
1,000 ppb.
Stock volume = target concentration × final volume ÷ stock concentration. Top the stock up to the final volume with diluent.
For gases (where ppm is usually by volume) and for liquids whose density is not 1 kg/L.