Greenhouse Gas Calculator

Combining Different Gases Into One Comparable Number

CO2, methane, and nitrous oxide all trap heat differently, so comparing raw masses across gases is misleading. Global warming potential (GWP) factors convert each gas into an equivalent mass of CO2, letting them be added into one meaningful total.

The Formula

CO2e = CO2 + (CH4 × 25) + (N2O × 298)

GWP factors shown are the IPCC AR4 100-year values: methane is 25 times more potent than CO2, nitrous oxide 298 times more potent.

Worked Example

3,000 kg CO2, 10 kg CH4, and 1 kg N2O:

CO2e = 3,000 + (10 × 25) + (1 × 298) = 3,548 kg CO2e

How to Use This Calculator

Enter the CO2 mass.
Enter CH4 and N2O masses if applicable (optional).
Select Calculate to get total CO2-equivalent emissions.

Related Calculations

Need methane mass from gas slip first? See the Methane Emission Calculator, or check CO2 from fuel carbon content in the CO2 Emissions Calculator.