Carbon Footprint Calculator

Calculate Your Footprint

Many people are concerned about climate change but feel helpless and overwhelmed with information about how to reduce their impact on the planet.

Although statistics and statements about the contribution of different activities are thrown around all the time, people have such different lifestyles that general advice is often not very useful. Therefore, the best way to manage your footprint is to start by measuring it.

By knowing how much each area of your life contributes to your carbon footprint you can focus your energy and motivation on making changes that really matter.

Estimate your footprint using the calculator on the right and you can read the full methodology below.

Energy

Diet

Air Travel

Waste

Transport

Lifestyle

Energy

Air Travel

Transport

Diet

Waste

Lifestyle

Calculate Your Footprint

Many people are concerned about climate change but feel helpless and overwhelmed with information about how to reduce their impact on the planet.

Although statistics and statements about the contribution of different activities are thrown around all the time, people have such different lifestyles that general advice is often not very useful. Therefore, the best way to manage your footprint is to start by measuring it.

By knowing how much each area of your life contributes to your carbon footprint you can focus your energy and motivation on making changes that really matter.

Methodology

Below you will find an in depth breakdown of the scientific research used to build our carbon calculator as well as a full list of all the references used.

To help put things into context we interviewed Tiago, the PHD student who built this calculator, on the Mossy Earth podcast.

This conversation goes over the process of building the calculator as well as the details of how each category influences your overall footprint.

Energy

Diet

Air Travel

Waste

Transport

Lifestyle

Below you will find an in depth breakdown of the scientific research used to build our carbon calculator as well as a full list of all the references used.

To help put things into context we interviewed Tiago, the PHD student who built this calculator, on the Mossy Earth podcast.

This conversation goes over the process of building the calculator as well as the details of how each category influences your overall footprint.

Background Information

What is a personal carbon footprint?

A personal carbon footprint is the total amount of greenhouse gas emissions caused by an individual.

Definitions and concepts

Carbon dioxide equivalent

Carbon footprints are measured in amount of carbon dioxide equivalent CO2e, the standard unit used to quantify greenhouse gas emissions. But what does this unit actually represent?

There are 7 major greenhouse gases that contribute to climate change: carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), sulfur hexafluoride (SF6) and nitrogen trifluoride (NF3). Some of theses gases lead to more warming than others for the same amount released into the atmosphere. This is reflected in a unit called the global warming potential which allows the emissions of these greenhouse gases to be converted into the amount of CO2 that would lead to the same amount of warming over a 100 year period. Using a standard unit makes it much easier to compare the impact of activities that emit different greenhouse gases.

Definitions and concepts

Carbon dioxide equivalent

Carbon footprints are measured in the amount of carbon dioxide equivalent CO2e, the standard unit used to quantify greenhouse gas emissions. But what does this unit actually represent?

There are 7 major greenhouse gases that contribute to climate change: carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), sulfur hexafluoride (SF6) and nitrogen trifluoride (NF3). Some of these gases lead to more warming than others for the same amount released into the atmosphere. This is reflected in a unit called the global warming potential which allows the emissions of these greenhouse gases to be converted into the amount of CO2 that would lead to the same amount of warming over a 100 year period. Using a standard unit makes it much easier to compare the impact of activities that emit different greenhouse gases.

Emission factors

Emission factors are essential for estimating a carbon footprint, they measure the CO2e emissions per unit of activity. For example, driving a car for 1 km leads to the emission of 0.04 kg of CO2e.

Life cycle analysis

Life cycle analysis is an approach to assess the environmental impact of a product or activity throughout its entire life cycle. For example, to estimate the carbon footprint of a smartphone you would need to assess the extraction and processing of raw materials, the manufacturing, transport, use and end of life of this product. Such in-depth studies are what allow us to estimate the carbon footprint of different products or activities and add them to your footprint in the calculator.

Emission factors

Emission factors are essential for estimating a carbon footprint, they measure the CO2e emissions per unit of activity. For example, driving a car for 1 km leads to the emission of 0.04 kg of CO2e.

Life cycle analysis

Life cycle analysis is an approach to assess the environmental impact of a product or activity throughout its entire life cycle. For example, to estimate the carbon footprint of a smartphone you would need to assess the extraction and processing of raw materials, the manufacturing, transport, use and end of life of this product. Such in-depth studies are what allow us to estimate the carbon footprint of different products or activities and add them to your footprint in the calculator.

Food & Waste

Diet

Estimating the carbon footprint of all you eat is not a simple task. However, enough research has been done that we can arrive at a good estimate. The carbon footprint associated with a range of food products has been estimated through life cycle analysis.

By combining the emission factors of different foods (i.e the CO2e emitted per amount consumed) by the average consumption rate among people following different diets we can estimate dietary carbon footprints. Several independent studies have followed this approach and although they arrive at different values, there is broad consensus on one finding: the lower the consumption of animal products the smaller the dietary carbon footprint. However, until recently, most studies ignored how food consumption is driving the replacement of native vegetation and soils (which are an important carbon sink) for agricultural land and how this increases the carbon footprint of food. In a recent study (1) this effect has been incorporated into a mathematical model leading to new estimates of dietary footprints which are the values we use in the calculator.

Diet

Estimating the carbon footprint of all you eat is not a simple task. However, enough research has been done that we can arrive at a good estimate. The carbon footprint associated with a range of food products has been estimated through life cycle analysis.

By combining the emission factors of different foods (i.e. the CO2e emitted per amount consumed) by the average consumption rate among people following different diets we can estimate dietary carbon footprints. Several independent studies have followed this approach and although they arrive at different values, there is broad consensus on one finding: the lower the consumption of animal products the smaller the dietary carbon footprint. However, until recently, most studies ignored how food consumption is driving the replacement of native vegetation and soils (which are an important carbon sink) for agricultural land and how this increases the carbon footprint of food. In a recent study (1) this effect has been incorporated into a mathematical model leading to new estimates of dietary footprints which are the values we use in the calculator.

Local and seasonal food

Buying local food and reducing food miles has received much attention as a measure to reduce carbon emissions. However simply buying local food may not reduce emissions because sometimes less carbon is emitted by producing food elsewhere and transporting it to where you live than to grow it locally where conditions may be unfavorable. Being mindful of where food comes from is still an important part of reducing our dietary footprint. In particular, avoiding food that is flown in and buying food that is both local and seasonal avoids many of these issues.

Transport has been estimated to account for about 11% of the food emissions associated with an average american diet (2) and 6% of an average global diet (3). From this we assume that, at most, by eating exclusively local and seasonal food could amount to a reduction of about 700 kg of CO2e per year.

Local and seasonal food

Buying local food and reducing food miles has received much attention as a measure to reduce carbon emissions. However simply buying local food may not reduce emissions as one might expect. In some cases, less carbon is emitted by producing food elsewhere and transporting it to where you live than to grow it locally where conditions may be unfavourable. E.g. green house grown tomatoes in the UK winter vs
Spanish tomatoes. Being mindful of where food comes from is still an important part of reducing our dietary footprint. In particular, avoiding food that is flown in and buying food that is both local and seasonal avoids many of these issues.

Transport has been estimated to account for about 11% of the food emissions associated with an average American diet (2) and 6% of an average global diet (3). From this we assume that, at most, by eating exclusively local and seasonal food could amount to a reduction of about 700 kg of CO2e per year.

Food waste

Food waste increases an individual’s carbon footprint in two ways.

First, by buying more food than necessary all the emissions associated with producing, transporting, packaging and preparing this additional food can be substantial. This accounts for the majority of emissions associated with domestic food waste.

Second, after you dispose of food it needs to be transported, processed and managed and this leads to additional end of life emissions. The study we used to obtain the estimates for dietary carbon footprints (1) assumes that the rate at which food that would normally be eaten is thrown away is 13% and that this accounts for about 10% of the diet’s footprint. Since emissions will be directly proportional to the amount of food wasted we can use this to adjust the dietary footprints above to specific amounts of food waste. For example, for someone that eats meat a few meals per week, their dietary carbon footprint will range from 5.9 tonnes of (CO2e if they waste 0 -10% of the food they buy) to 7.6 (if they waste 20 -30%).

Food waste

Food waste increases an individual’s carbon footprint in two ways.

First, by buying more food than necessary all the emissions associated with producing, transporting, packaging and preparing this additional food can be substantial. This accounts for the majority of emissions associated with domestic food waste.

Second, after you dispose of food it needs to be transported, processed and managed and this leads to additional end of life emissions. The study we used to obtain the estimates for dietary carbon footprints (1) assumes that the rate at which food that would normally be eaten is thrown away is 13% and that this accounts for about 10% of the diet’s footprint. Since emissions will be directly proportional to the amount of food wasted we can use this to adjust the dietary footprints above to specific amounts of food waste. For example, for someone that eats meat a few meals per week, their dietary carbon footprint will range from 5.9 tonnes of (CO2e if they waste 0 -10% of the food they buy) to 7.6 (if they waste 20 -30%).

Recycling

When materials are recycled rather than being sent to landfill, their use prevents the emissions needed to extract and process the raw materials needed to make new products and packaging. However the additional transport and processing associated with recycling leads to further emissions.

We estimated the net carbon footprint savings associated with recycling comprehensively based on the latest official uk statistics on waste (4) lead to a value of 100 kg of CO2e per year, which is comparable to the values reported in another study (5).

Recycling

When materials are recycled rather than being sent to landfill, their use prevents the emissions needed to extract and process the raw materials needed to make new products and packaging. However, the additional transport and processing associated with recycling does also lead to further emissions.

We estimated the net carbon footprint savings associated with recycling comprehensively based on the latest official UK statistics on waste (4) lead to a value of 100 kg of CO2e per year, which is comparable to the values reported in another study (5).

Air Travel

To calculate emissions from flying we need to know the distance you fly over a year and multiply it by the appropriate emission factor (i.e. the estimate of greenhouse gas emissions per amount of distance travelled). We use the emission factors provided by the latest official report (6) by the UK Department for Business Energy & Industrial Strategy (BEIS). Several emission factors are provided, so here we explain which ones we use in the calculator and why.

We choose to use emission factors that take into account the stronger warming effect of emissions by air travel compared to other sources. There are multiple reasons for this, including the fact that air travel emissions occur at higher altitudes. There is currently no consensus on the magnitude of these effects but it is expected to be large. All our calculations use a radiative forcing index of 1.9 as recommended by the BEIS (6) and the United Nations Framework Convention on Climate Change. See this article  for a discussion of radiative forcing in aviation, and for a justification of the 1.9 multiplier see the BEIS report (6).

  1. We have chosen emission factors provided for International flights as this is a summary measure that will provide the best estimate of the emission factor for a user without specifying the exact route or location.  
  2.  
  3. We use cabin-class specific emission factors. Passengers using more spacious seating are accountable for a greater share of the aircraft’s emissions. If the space taken up by first class seats was used by economy class seats the number of passengers on the airplane could increase such that each one would be accountable for a smaller share of the total emissions. Since emission factors differ widely among different classes, it is very important to include this component in the calculations.

We choose to use emission factors that take into account the stronger warming effect of emissions by air travel compared to other sources. There are multiple reasons for this, including the fact that air travel emissions occur at higher altitudes. There is currently no consensus on the magnitude of these effects, but it is expected to be large. All our calculations use a radiative forcing index of 1.9 as recommended by the BEIS (6) and the United Nations Framework Convention on Climate Change. See this article  for a discussion of radiative forcing in aviation, and for a justification of the 1.9 multiplier see the BEIS report (6).

  1. We have chosen emission factors provided for International flights as this is a summary measure that will provide the best estimate of the emission factor for a user without specifying the exact route or location.  
  2.  
  3. We use cabin-class specific emission factors. Passengers using more spacious seating are accountable for a greater share of the aircraft’s emissions. If the space taken up by first class seats was used by economy class seats the number of passengers on the airplane could increase such that each one would be accountable for a smaller share of the total emissions. Since emission factors differ widely among different classes, it is very important to include this component in the calculations.

Commuting

Emission factors

To estimate emissions associated with car transport we use the latest emission factors provided by BEIS (6). These are different depending on car type (Diesel, Petrol, Hybrid ,PHEV or Electric) and car size (small,medium or large). For electric cars we further adjust these emission factors based on the country and/or state of residence. Emissions associated with electricity consumption vary widely between countries and states because of the way   electricity is produced, so this is a very important part of estimating the carbon footprint of driving an electric car. To illustrate, driving a medium sized electric car for 20 000 km in a year would be associated with the emission of a tonne of CO2e if electricity was bought in the UK, half a tonne if bought in Vermont, USA and about 18 tonnes if bought in Wyoming USA. We further adjust for the % of energy derived from renewable energy (see electricity emission factors below). For some countries we do not have specific emission factors in which case we use the global average.

Emission factors

To estimate emissions associated with car transport we use the latest emission factors provided by BEIS (6). These are different depending on car type (Diesel, Petrol, Hybrid ,PHEV or Electric) and car size (small, medium or large). For electric cars we further adjust these emission factors based on the country and/or state of residence. Emissions associated with electricity consumption vary widely between countries and states because of the way electricity is produced, so this is a very important part of estimating the carbon footprint of driving an electric car. To illustrate, driving a medium sized electric car for 20,000 km in a year would be associated with the emission of a tonne of CO2e if electricity was bought in the UK, half a tonne if bought in Vermont, USA and about 18 tonnes if bought in Wyoming USA. We further adjust for the % of energy derived from renewable energy (see electricity emission factors below). For some countries we do not have specific emission factors in which case we use the global average.

Ride sharing

To estimate the share of emissions you are accountable for due to car transportation we divide the total amount emitted by the car by the number of passengers.

Motorbike

As with cars,we use the latest emission factors for motorbike driving provided in the government BEIS report (6).

Regional train

For transport by train we use the emission factor provided for national rail (6) and assume an average speed of 100 km/h

Light rail, tram and underground

Since the difference between the emission factors provided by for light rail and London Underground are very small (6), we combine the two into a single category and use an average emission factor. We assume an average speed of 20 km/h based on data from The European Research Advisory Council.(7)

Ride sharing

To estimate the share of emissions you are accountable for due to car transportation we divide the total amount emitted by the car by the number of passengers.

Motorbike

As with cars, we use the latest emission factors for motorbike driving provided in the government BEIS report (6).

Regional train

For transport by train we use the emission factor provided for national rail (6) and assume an average speed of 100 km/h

Light rail, tram and underground

Since the difference between the emission factors provided by for light rail and London Underground are very small (6), we combine the two into a single category and use an average emission factor. We assume an average speed of 20 km/h based on data from The European Research Advisory Council.(7)

Home Energy

The aim of this category is to estimate the carbon footprint of energy consumption in your household. We estimate the total emissions for the household and divide it by the occupants. We have built a database with country specific emission factors and average energy consumption levels from multiple sources (1-13), which helps us achieve more accurate estimates.

Electricity

If you chose to introduce the exact kwh of electricity you consumed from your electricity bill we multiply this by the country-specific emission factor (if available, otherwise a global average is used) to estimate the emissions. If you choose to estimate your consumption based on averages, we assign you the average electricity consumption in your country and adjust this value depending on whether you think your consumption is above or below average. To determine above or below average consumption values we take into account studies that have analysed how much variation in electricity consumption there is between households (14).  

If all the energy you use at home comes from renewable sources we use the average emission factors for wind, solar and hydroelectric energy production provided by the IPCC (15). Although emission factors for these sources are very low they still require infrastructure development and introduce changes in the landscape and so are not emission free. If a percentage of your electricity comes from renewable sources the final emission factor used will be a weighted average of your country's emission factor and the one of renewable energy.

Electricity

If you chose to introduce the exact kwh of electricity you consumed (based on your electricity bill), we multiply this by the country-specific emission factor (if available, otherwise a global average) to estimate the emissions. If you choose to estimate your consumption based on averages, we assign you the average electricity consumption in your country and adjust this value depending on whether you think your consumption is above or below average. To determine above or below average consumption values we take into account studies that have analysed how much variation in electricity consumption there is between households (14).  

If all the energy you use at home comes from renewable sources, we use the average emission factors for wind, solar and hydroelectric energy production provided by the IPCC (15). Although emission factors for these sources are very low, they still require infrastructure development and introduce changes in the landscape and so are not emission free. If a percentage of your electricity comes from renewable sources, the final emission factor used will be a weighted average of your country's emission factor and the one of renewable energy.

Other fuels

If you provide the exact consumption levels of natural gas,LPG, Burning oil or wood we estimate the emissions using the latest emission factors for each fuel (6). If you choose to estimate your consumption based on averages, we use the typical consumption values reported for european countries (16).

Other fuels

If you provide the exact consumption levels of natural gas, LPG, burning oil or wood, we estimate the emissions using the latest emission factors for each fuel (6). If you choose to estimate your consumption based on averages, we use the typical consumption values reported for European countries (16).

General Consumption

Clothing

The unsustainability of fast fashion has deservedly received much attention. Each clothing item has a carbon footprint and frequent buying can have a substantial impact. The Carbon Trust provides a detailed analysis of the carbon footprint of clothing items (17). From this we estimate the average carbon footprint of an item of clothing at 3kg of CO2e and get the yearly total by multiplying it by the number of items bought. Note that this excludes the use phase emissions associated with washing and drying because these are covered by the home energy part of your footprint.

Electronics

The estimates of the carbon footprint of electronic products used in our calculator are taken from a recent study (18).

Car

If you bought a car over the last year we add the carbon footprint of manufacturing it (19) to your personal carbon footprint. Although you may continue to use the car in the future, this gives you a better idea of where your car’s emissions come from (production versus driving) than other approaches.

Clothing

The unsustainability of fast fashion has deservedly received much attention in recent years. Each clothing item has a carbon footprint and frequent buying can have a substantial impact. The Carbon Trust provides a detailed analysis of the carbon footprint of clothing items (17). From this we estimate the average carbon footprint of an item of clothing at 3kg of CO2e and get the yearly total by multiplying it by the number of items bought. Note that this excludes the use phase emissions associated with washing and drying because these are covered in the home energy part of your footprint.

Electronics

The estimates of the carbon footprint of electronic products used in our calculator are taken from a recent study (18).

Car

If you bought a car over the last year, we add the carbon footprint of manufacturing it (19) to your personal carbon footprint. Although you may continue to use the car in the future, this gives you a better idea of where your car’s emissions come from (production versus driving).

Sustainable target

To put your carbon footprint into perspective we compare it with a target personal footprint of 1.61 t. This is a footprint that would be low enough to prevent a warming of 2°C if sustained up to 2100 (20). Increasing population size may further reduce this value and technological breakthroughs that reduce emissions may increase it but for now we take it as a useful guideline.

 

Limitations

We have made an effort to design a calculator that is accurate and based on the latest research, is user friendly, is sufficiently flexible to be useful to a wide range of people and is comprehensive. However, as detailed in the methodology we had to make several assumptions and simplifications in order to balance these requirements. If you have any questions or suggestions, please get in touch at tiago@mossy.earth

References

1. Searchinger T, Wirsenius S, Beringer T, Dumas P. Assessing the efficiency of changes in land use for mitigating climate change. Nature. 2019. Available at: https://www.nature.com/articles/s41586-018-0757-z

2. Weber C, Matthews H. Food-Miles and the Relative Climate Impacts of Food Choices in the United States. Environmental Science & Technology. 2008. Available at: https://pubs.acs.org/doi/abs/10.1021/es702969f

3. Poore J, Nemecek T. Reducing food’s environmental impacts through producers and consumers. Science. 2018. Available at: https://science.sciencemag.org/content/360/6392/987

4. Department for Environment Food & Rural Affairs. UK Statistics on Waste. 2019. Available at: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/784263/UK_Statistics_on_Waste_statistical_notice_March_2019_rev_FINAL.pdf


5. Wynes S, Nicholas K. The climate mitigation gap: education and government recommendations miss the most effective individual actions. Environmental Research Letters. 2017;12(7):074024.


6. Department for Business Energy & Industrial Strategy. 2018 Government GHG conversion factors for company reporting. 2018. Available at: https://www.gov.uk/government/collections/government-conversion-factors-for-company-reporting


7. The European Rail Research Advisory Council. Metro, light rail and tram systems in Europe. 2012. Available at: https://www.uitp.org/metro-light-rail-and-tram-systems-europe

8. Association of Issuing Bodies. European residual mixes 2018. 2019. Available at: https://www.aib-net.org/facts/european-residual-mix

9. United States Environmental Protection Agency. Emissions & Generation Resource Integrated Database (eGRID). 2018. Available at: https://www.epa.gov/energy/emissions-generation-resource-integrated-database-egrid

10. National Inventory Report. Greenhouse Gas Sources and Sinks in Canada. 2018. http://publications.gc.ca/site/archivee-archived.html?url=http://publications.gc.ca/collections/collection_2018/eccc/En81-4-2016-3-eng.pdf

11. Department of the Environment and Energy. National Greenhouse Accounts Factors.2018.
Other: https://www.environment.gov.au/climate-change/climate-science-data/greenhouse-gas-measurement/publications/national-greenhouse-accounts-factors-july-2018

12. Climate Transparency. The Brown to Green Report. 2018. Available at: https://www.climate-transparency.org/g20-climate-performance/g20report2018#1531904804037-423d5c88-a7a7

13. World Energy Council. Average electricity consumption per electrified household. 2014. Available at: https://wec-indicators.enerdata.net/household-electricity-use.html

14. Janine Morley and Mike Hazas. The significance of difference: Understanding variation in household energy consumption. ECEEE. 2011. Available at: https://www.eceee.org/library/conference_proceedings/eceee_Summer_Studies/2011/8-dynamics-of-consumption160/the-significance-of-difference-understanding-variation-in-household-energy-consumption/

15. Working Group III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Annex III: Technology-specific cost and performance parameters. In: Climate Change 2014: Mitigation of Climate Change. Cambridge University Press. 2014. Available at: https://www.cambridge.org/core/books/climate-change-2014-mitigation-of-climate-change/technologyspecific-cost-and-performance-parameters/E8BDDCAB19FB9E956519DF1431AC7E8A

16. Johnson E. Carbon footprints of heating oil and LPG heating systems. Environmental Impact Assessment Review. 2012. Available at: https://www.sciencedirect.com/science/article/abs/pii/S0195925512000066

17. Carbon trust. International Carbon Flows - Clothing. 2011. Available at: https://www.carbontrust.com/resources/reports/advice/international-carbon-flows/

18. Low Carbon Vehicle Partnership. Life Cycle CO2e Assessment of Low Carbon Cars 2020 - 2030. 2011. Available at: https://www.lowcvp.org.uk/news,lowcvp-study-highlights-importance-of-measuring-whole-life-carbon-emissions_1644.htm

19. Belkhir L, Elmeligi A. Assessing ICT global emissions footprint: Trends to 2040 & recommendations. Journal of Cleaner Production. 2018. Available at: https://www.sciencedirect.com/science/article/pii/S095965261733233X

20. O’Neill D, Fanning A, Lamb W, Steinberger J. A good life for all within planetary boundaries. Nature Sustainability. 2018. Available at: https://www.nature.com/articles/s41893-018-0021-4