Why gas conversions are different
Gas PPM is usually a volume ratio, while mg/m³ is a mass concentration. Converting between them requires molar mass and gas conditions.
Temperature and pressure affect how much gas mass occupies a cubic meter, so they should not be ignored in professional calculations.
Molar mass is essential
The same PPM value represents different mg/m³ values for different gases because each gas has a different molar mass.
For example, CO₂ and ammonia cannot share the same mass conversion unless their molar masses are accounted for.
Calculator workflow
Use the PPM to mg/m³ calculator when starting from a gas PPM reading. Use the mg/m³ to PPM calculator when interpreting a mass concentration report.
Frequently asked questions
Can I convert gas PPM without molar mass?
No. Molar mass is required to convert a gas volume ratio into mass concentration.
Why do temperature and pressure matter?
They affect gas density, which changes the mg/m³ value for the same PPM ratio.