Parts per Million (ppm) Conversion

Parts Per Million, also known as "ppm", is a method of expressing low concentrations of impurities in a mixture. The unit can be expressed in moles, volume or weight per million of the same units. Lower concentration may be expressed in parts per billion (ppb) or parts per trillion (ppt).

Mathematically, ppm is equivalent to the following:

  • 1.000% = 10,000 ppm
  • 0.100% = 1,000 ppm
  • 0.010% = 100 ppm
  • 0.001% = 10 ppm

In general, the ppm designation is used for impurities once the content level descends below 0.1%.

As one more example, a popular gas from our website contains 10 ppm H2S, 50 ppm CO2, 2.5% CH4, 18% O2 and Balance N2.  In percentage values, this can be summarized as follows:

  • 0.001% H2S
  • 0.005% CO2
  • 2.500% CH4
  • 18.000% O2
  • 79.494% N2
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