PPM, Percent, and PPB Converter
Concentration unit conversions for chemistry.
ppm
250.0000
%
0.025000
‰
0.2500
ppb
250000.00
In dilute aqueous solution
250.0000 mg/L
250.0000 mg/kg
0.250000 g/L
0.250000 g/kg
1 ppm = 1 mg/kg = 1 mg/L (for dilute aqueous solutions where solution density ≈ 1 g/mL). 1% = 10,000 ppm. The mg/L identity breaks down for non-aqueous or very dense solutions, where you should use mass fraction directly.
About
Enter a value in ppm, percent, per mille, or ppb. Get equivalents in all four. For dilute aqueous solutions, also shows mg/L and mg/kg. The mg/L identity holds because 1 L of dilute solution weighs about 1 kg.
How to use
- Enter a value and pick its unit.
- Read all four equivalents.
FAQ
Why does 1 ppm = 1 mg/L?+
Only for dilute aqueous solutions where 1 L of water weighs 1 kg. So 1 mg in 1 kg is 1 part per million by mass. The identity breaks down for dense liquids, gases, or solids.