ppmv to mg/m3 Gas Concentration Converter

Convert gas concentration
between ppmv and mg/m3. Use molecular weight,
temperature, and absolute pressure. Compare VOC, exhaust-gas,
indoor-air, and process-gas measurements.

Uses the ideal gas law
for a dry gas. Uses the temperature and pressure
you enter. Water vapor, real-gas effects,
ppm by mass, and liquid concentration
are outside the scope of this tool.

Conversion mode:

Concentration: ppmv or mg/m3, depending on the selected mode

Molecular weight: g/mol

Temperature:

Unit:

Absolute pressure:

Unit:

Conversion Result

Formula

mg/m3 = ppmv * molecular_weight * pressure_pa / (R * temperature_k) / 1000

ppmv = mg/m3 * 1000 * R * temperature_k / (molecular_weight * pressure_pa)

Here, R = 8.314462618 J/(mol K). Pressure must be absolute pressure, not gauge pressure.

How to Use the Result

ppmv is a gas volume ratio expressed per one million parts by volume.
mg/m3 is mass per unit gas volume at the entered temperature and pressure.
At the same ppmv, a gas with larger molecular weight gives a larger mg/m3 value.
At the same ppmv and molecular weight, higher pressure increases mg/m3 and higher temperature decreases mg/m3.

Example

CO2 with molecular weight 44.01 g/mol at 25 C and 101.325 kPa(abs): 1 ppmv is about 1.80 mg/m3.

Input Notes

Enter the molecular weight of the target gas component, not the average molecular weight of the whole gas mixture.
Enter absolute pressure. If you have gauge pressure, add atmospheric pressure before using this converter.
Use the same temperature and pressure basis as the measurement, specification, or regulation you are comparing against.
For wet gas, humidity correction, real-gas effects, or legally defined reference oxygen conditions, apply the relevant method separately.