Conversion Calculator

"mg/m3 to ppm" or "ppm to mg/m3"

The conversion equation is based on 25 ºC and 1 atmosphere:

X ppm = (Y mg/m3)(24.45)/(molecular weight)


Y mg/m3 = (X ppm)(molecular weight)/24.45

Fill in either the "ppm" value (X) or the "mg/m3" value (Y) AND the molecular weight of the compound. Then press the "Calculate" button.

Remember to consider significant digits in your use of the answer.

To determine molecular weight, add the atomic weights of all atoms present in the chemical formula for a particular substance. Periodic Table (courtesy of Los Alamos National Laboratory).

Page last reviewed: September 21, 2021
Page last updated: September 21, 2021
Content source: National Institute for Occupational Safety and Health  Division of Science Integration