CNaught's carbon emissions and footprint calculator is a free interactive tool to help understand the climate impact of your actions. Greenhouse gases (GHGs), including carbon dioxide, methane, and nitrous oxide are emitted through the production and consumption of fossil fuels, food, manufactured goods, and buildings. Below, you will find the specific methodology CNaught uses to estimate your emissions.

Commercial Flights

CNaught uses distance flown as the single input for calculating the emissions attributed to a passenger on a typical commercial flight. The distance in miles between two city pairs can be calculated using MileMarker from WebFlyer. The calculator converts this distance into kilometers then multiplies it by the average carbon intensity of flights departing the United States of 95 grams of CO2e per passenger kilometer as provided by the International Council on Clean Transportation for 2019.

Additional factors that could affect this estimate include: class of airfare, type of airplane, load factor, and cargo utilization.

Ground Transportation

CNaught uses two inputs to calculate emissions due to ground transportation: (1) type of vehicle which can be (a) passenger car, van, or SUV; (b) small bus; (c) school bus; or (d) coach bus and (2) miles traveled.

The miles traveled input is divided by the average miles per gallon for the vehicle class as provided by the sources listed below and then the resulting number of gallons is multiplied by the appropriate fuel emissions coefficient in kilograms CO2 / gallon as provided by the U.S. EPA. For school and coach buses, we use diesel. For the other categories, we use unleaded.

Additional factors that affect the accuracy of this estimate include: the miles per gallon of the actual vehicle used, the fuel type of that vehicle, the biofuel content (e.g., ethanol) of the fuel used, and the route driven.

Ground shipping

CNaught uses two inputs for calculating the emissions attributed to ground shipping: the distance traveled in miles and the total mass of the shipment in kilograms.For the long-haul portion of ground shipments, the distance is converted into kilometers then multiplied by the mass and the average carbon intensity of road freight of 0.097 grams of CO2e per kg-km as provided by the Global Logistics Emissions Council for 2019.

For the final segment of delivery to a final destination, we assume a distance traveled of 20 miles and use an average carbon intensity of package vans of 1.135 grams of CO2e per kg-km as provided by the Global Logistics Emissions Council.

The emissions estimates for the long-haul and final leg are added together to provide an estimate of the total emissions for ground shipments.

Additional factors that affect the accuracy of this estimate include: the fuel efficiency of actual vehicles used (including any non-truck vehicles), density of the package, and length of distance traveled during the final leg.

Air freight

CNaught uses two  inputs for calculating the emissions attributed to air freight: the distance flown in miles and the total mass of the shipment in kilograms. The distance is converted into kilometers then multiplied by the mass and the average carbon intensity of air freight of 1.06 grams of CO2e per kg-km as provided by the Global Logistics Emissions Council for 2019.

Additional factors that could affect the accuracy of this estimate include: the equipment flown, carrier, weather conditions, source of fuel, and load factor.

Passenger Train

CNaught uses distance traveled as the single input for calculating the emissions attributed to a passenger on a train.That mileage is multiplied by the average carbon intensity of electric Amtrak trains operating in the northeastern United States, which is 0.134 pounds of CO2e per passenger mile, according to the EPA.

Additional factors that could affect the accuracy of this estimate include: the type of train and the load factor.

Office space

CNaught uses the size of the office in square feet as the single input to calculate emissions due to usage of office space. This area is multiplied by the average carbon intensity of office space of 8.6 kg CO2e per square foot per year as provided by the EPA.

Additional factors that affect the accuracy of this estimate include: the source of power for building HVAC, the actual source of electricity used at a specific location of the office, any efficiency measures taken by landlord and/or tenant, and the number of individuals using the office space.