mg/m³ to PPM Gas Calculator
Your gas monitor reads mg/m³ but the safety data sheet lists the limit in PPM. Reverse the conversion: PPM = mg/m³ × 24.45 ÷ MW.
Calculator
mg/m³ to PPM Gas Calculator
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Your gas monitor reads mg/m³ but the safety data sheet lists the limit in PPM. Reverse the conversion: PPM = mg/m³ × 24.45 ÷ MW.
How to use this calculator
- Enter mg/m³.
- Enter molecular weight.
- Get PPM.
The formula
Exact reverse of PPM → mg/m³.
What the units mean
PPM (parts per million) — one part of solute per million parts of the total mixture. The workhorse unit for trace concentrations in water, air, and food.
Assumption: Gas conversions depend on temperature and pressure. This uses 25 °C and 1 atm (molar volume 24.45 L/mol); correct the molar volume if your conditions differ.
Worked example
90 mg/m³ CO₂ (MW 44.01): 90 × 24.45 ÷ 44.01 ≈ 50 PPM.
Quick reference
| mg/m³ | PPM (CO₂) |
|---|---|
| 45 | 25 |
| 90 | 50 |
| 180 | 100 |
CO₂ at 25°C, 1 atm.
Where you will actually use this
Monitors and regulations often disagree on units.
- Monitor interpretation
- Compliance checks
- Incident investigation
Mistakes that give wrong answers
- Wrong MW
- Ignoring conditions
Key takeaways
- Formula: PPM = mg/m³ × 24.45 ÷ MW [25°C, 1 atm]
- Remember: CO₂ at 25°C, 1 atm.
- Watch out for: Wrong MW
- Next step: run your own numbers in the calculator above, then verify with a measurement — calculated values are only as good as the inputs.
Frequently asked questions
How do you convert mg/m³ to PPM?
Multiply by 24.45 and divide by molecular weight (25°C, 1 atm).