Car Emissions Calculator Formula

Understand the math behind the car emissions calculator. Each variable explained with a worked example.

Use the Car Emissions Calculator

Formulas Used

Annual CO2 Emissions

co2_metric_tons = total_lbs / 2204.6

Annual CO2 (lbs)

co2_lbs = total_lbs

Gallons of Fuel Used

gallons_per_year = gallons_used

Variables

VariableDescriptionDefault
annual_milesAnnual Miles Driven(miles)12000
mpgFuel Economy(mpg)28
fuel_co2_per_gallonCO2 per Gallon of Fuel(lbs)19.6
gallons_usedDerived value= annual_miles / mpgcalculated
total_lbsDerived value= gallons_used * fuel_co2_per_galloncalculated

How It Works

How to Calculate Car CO2 Emissions

Vehicle emissions depend on how far you drive and how efficient your car is.

Formula

CO2 (lbs) = (Annual Miles / MPG) * CO2 per Gallon

  • Gasoline produces about 19.6 lbs CO2 per gallon
  • Diesel produces about 22.4 lbs CO2 per gallon

    • Divide pounds by 2,204.6 to get metric tons.

    Worked Example

    You drive 12,000 miles per year in a car that gets 28 mpg.

    annual_miles = 12000mpg = 28fuel_co2_per_gallon = 19.6
    1. 01Gallons used: 12,000 / 28 = 428.6 gallons
    2. 02CO2 in lbs: 428.6 * 19.6 = 8,400 lbs
    3. 03CO2 in metric tons: 8,400 / 2,204.6 = 3.81 metric tons

    Ready to run the numbers?

    Open Car Emissions Calculator