Common gas library

PPM to mg/L for Gases Calculator

Select a common gas, enter its ppm reading and operating conditions, and get an instant mass concentration.

Formula mg/L = ppmv × selected gas MW × P ÷ (R × T) × 0.001

Live conversion

PPM to mg/L for Gases Calculator

Updates live
Concentration — mg/L
Concentration — mg/m³

Results assume non-negative inputs and the unit basis shown.
Conversion basis

The formula behind the result

mg/L = ppmv × selected gas MW × P ÷ (R × T) × 0.001

The gas list supplies molar mass automatically. Results assume ppm by volume and ideal-gas behavior.

Compare common gases correctly

The same ppmv reading produces a different mg/L result for each gas because molar masses differ. Heavier molecules contribute more mass at the same mole fraction.

The selector includes frequently monitored gases and fills in each compound's molar mass automatically.

Standard and actual conditions

Mass concentration changes with temperature and absolute pressure. There is no single universal standard temperature, so use the conditions named in your regulation, instrument, or method.

For humid gas or strongly non-ideal conditions, a more detailed correction may be required.

Quick reference

Conversion examples

Input Conditions Result
100 ppmv CO₂ 25 °C, 1 atm 0.17988 mg/L
100 ppmv O₂ 25 °C, 1 atm 0.13078 mg/L
100 ppmv SO₂ 25 °C, 1 atm 0.26186 mg/L
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CO₂ gas concentration CO₂ PPM to mg/L

Convert carbon dioxide ppm by volume to mg/L using temperature, pressure, and the molar mass of CO2.

 Custom gas PPM to mg/L for Gas

Convert gas ppmv to mg/L with custom molar mass, temperature, and pressure using the ideal gas law.

 O₂ gas concentration Oxygen PPM to mg/L

Convert gaseous oxygen ppmv to mg/L and mg/m3 using temperature, absolute pressure, and oxygen molar mass.

Frequently Asked Questions

Why do different gases give different mg/L values?
PPMv is a mole fraction. Converting moles to mass introduces the selected gas's molar mass.
What if my gas is not listed?
Use the custom gas calculator and enter the compound's molar mass in g/mol.
Is mg/m³ always 1,000 times mg/L?
Yes. One cubic meter contains 1,000 liters, so the numerical mg/m³ value is 1,000 times the mg/L value.