What is a carbon footprint - definition

A carbon footprint is defined as:

The total amount of greenhouse gases produced to directly and indirectly support human activities, usually expressed in equivalent tons of carbon dioxide (CO2).

In other words: When you drive a car, the engine burns fuel which creates a certain amount of CO2, depending on its fuel consumption and the driving distance. (CO2 is the chemical symbol for carbon dioxide). When you heat your house with oil, gas or coal, then you also generate CO2. Even if you heat your house with electricity, the generation of the electrical power may also have emitted a certain amount of CO2. When you buy food and goods, the production of the food and goods also emitted some quantities of CO2.

Your carbon footprint is the sum of all emissions of CO2 (carbon dioxide), which were induced by your activities in a given time frame. Usually a carbon footprint is calculated for the time period of a year.

The best way is to calculate the carbon dioxide emissions based on the fuel consumption. In the next step you can add the CO2 emission to your carbon footprint. Below is a table for the most common used fuels:


  • For each (UK-) gallon of petrol fuel consumed, 10.4 kg carbon dioxide (CO2) is emitted.
  • For each (US-) gallon of gasoline fuel consumed, 8.7 kg carbon dioxide (CO2) is emitted.
  • If your car consumes 7.5 liter diesel per 100 km, then a drive of 300 km distance consumes 3 x 7.5 = 22.5 liter diesel, which adds 22.5 x 2.7 kg = 60.75 kg CO2 to your personal carbon footprint.
fuel type unit
CO2 emitted per unit
Petrol 1 gallon (UK)
10.4 kg
1 liter
2.3 kg
Gasoline  1 gallon (USA)
8.7 kg
Gasoline  1 liter
2.3 kg
Diesel 1 gallon (UK)
12.2 kg
Diesel  1 gallon (USA)
9.95 kg 
1 liter
2.7 kg
Oil (heating)
1 gallon (UK)
13.6 kg
Oil (heating)  1 gallon (USA)
11.26 kg 
Oil (heating)
1 liter 3 kg

Each of the following activities add 1 kg of CO2 to your personal carbon footprint:

  • Travel by public transportation (train or bus) a distance of 10 to 12 km (6.5 to 7 miles)
  • Drive with your car a distance of 6 km or 3.75 miles (assuming 7.3 litres petrol per 100 km or 39 mpg)
  • Fly with a plane a distance of 2.2 km or 1.375 miles.
  • Operate your computer for 32 hours (60 Watt consumption assumed)
  • Production of 5 plastic bags
  • Production of 2 plastic bottles
  • Production of 1/3 of an American cheeseburger (yes, the production of each cheeseburger emits 3.1 kg of CO2!)

To calculate the above contributions to the carbon footprint, the current UK mix for electricity and trains was taken into account.

Carbon dioxide is a so called greenhouse gas causing global warming . Other greenhouse gases which might be emitted as a result of your activities are e.g. methane and ozone. These greenhouse gases are normally also taken into account for the carbon footprint. They are converted into the amount of CO2 that would cause the same effects on global warming (this is called equivalent CO2 amount).

Few people express their carbon footprint in kg carbon rather than kg carbon dioxide. You can always convert kg carbon dioxide in kg carbon by multiplying with a factor 0.27 (1'000 kg CO2 equals 270 kg carbon). See my comment to the article about personal responsibility for global warming .

The carbon footprint is a very powerful tool to understand the impact of personal behaviour on global warming. Most people are shocked when they see the amount of CO2 their activities create! If you personally want to contribute to stop global warming, the calculation and constant monitoring of your personal carbon footprint is essential.

For registered users, there is a carbon footprint calculator on this website, which allows to store individual activities like, e.g. travelling by car, train, bus or air plane, fuel consumptions, electricity bills and so on (we call the individual contributions "carbon stamps"). You can then see the amount of CO2 created for each individual activity. You can do this either in advance and use it as a help for decisions or afterwards to continually sum up your carbon dioxide emissions. Klick here to see a sample carbon footprint with some activities.

An off-line carbon footprint and primary energy consumption calculator (Excel sheet) is already available in the download section.

There are graphs available on this site for the CO2 emissions per capita by country (average carbon footprint by country). In the medium- and long term, the carbon footprint must be reduced to less than 2'000 kg CO2 per year and per person. This is the maximum allowance for a sustainable living .




I too would like to see the chemical formula for the combustion of gasolene or diesel.
I don't see how more CO2 by weight can be produced than the liquid being combusted.

Oxidation (combustion) process

Please have a look at the link provided in the reply just above your question. If you can't follow those explanations, please post your further questions there.

Its easy

Just beacuse burning 1litre of fuel doesn't create 2.3kg of carbon doesn't mean its footprint can't be greater than its actual weight.
To create 1 litre of fuel takes a process of refining more than 1 litre of oil.
You have to then use all types of energy to create the fuel which you need to burn coal and oil to create the enrgy to heat the oil and refine it
You need to ship the oil to the petrol station from the other side of the world whihc takes carbon.
And so on and so on

So yes most products if not all have a carbon footprint greater than there core carbon ingredients, hence the turn footprint and not say emissions.

Shock even the water you use in your tap and to water on your lawn has a carbon footprint!
It didn't make it all the way in to those pipes and to your house with no energy did it.

dunno man, google it

dunno man, google it

Product of 5 plastic bags = 1kg of CO2

Hello. Would it be possible to provide further citation or explanation of the following metric? Production of 5 plastic bags = 1kg of CO2. We are trying to verify the carbon impact of plastic bag usage and this would be extremely useful information. We could site provided a sound methodology. Thanks so much!

CO2 emission for plastic bags and water bottles

The following reasoning led to the above mentioned carbon dioxide (CO2) emission for plastics:

  • The production of 1 kg of polyethylene (PET or LDPE), requires the equivalent of 2 kg of oil for energy and raw material (see here). Polyethylene PE ist the most commonly used plastic for plastic bags.
  • Burning 1 kg of oil creates about 3 kg of carbon dioxide (see e.g. our offline carbon footprint calculator). In other words: Per kg of plastic, about 6 kg carbon dioxide is created during production and incineration.
  • A plastic bag has a weight in the range of about 8 g to 60 g depending on size and thickness. For the further calculation, it now depends on which weight for a plastic bag you actually use. A common plastic carrying bag in our household had a weight between 25 g and 40 g. So I took the average of 32.5 g.
  • Take the above relation between kg plastics and kg of carbon dioxide, and you get about 200 g carbon dioxide for 32.5 g of plastic, which is the equivalent of the average plastic carrying bag in our household. Or in other words: For 5 plastic bags you get 1 kg of CO2.

Of course you'll find different figures on the Internet. The main factors are the weight of the plastic bag and whether the grey energy (energy used for production) is taken into account.

There is now a separate text available about the CO2 emissions for plastic bags and plastic bottles.



Thanks for the thorough explanation. If we were to cite this information, do you have a preference of how you would like to be featured?


I liked this site soooo much and the info is great. I will definitely tell my friends about this and thanks again. :)

Plastic bags

Could you tell me the amount of CO2 emitted for different types of plastics.. HDPE, LDPE, PET etc....each would have different amount of Co2 emitted.. what are their details ??


Carbon footprint for plastic bags and water bottles

Due to many uncertainties, it is not realistic to give different amounts of CO2 emitted for different types of plastics. For a bottle or for a plastic bag, the amount of plastic used is much more important.

Some more information is available in our separate article about CO2 emission of plastic bags and in the links within the article.



Thanks a lot. I am doing my project and this has a very good and exact information that I need.

Plastic bags

I disagree with your worked example.

A disposable plastic bag is not 32.5g, for a start. A heavy-use renewable bag might be, but not a disposable.
Disposable plastic bags are closer to 10g in weight.
The energy cost of polyethylene is c. 74MJ/kg produced.
Crude oil has a calorific value of c. 45MJ/kg.
So the production of 1kg of plastic takes around 74/45, or around 1.65kg of oil.
That 1.65kg is, using your calcs, worth around 4.95kg of CO2.
At 10g per bag, that's 100 bags for 4.95kg of CO2, or around 49.5g per bag.
That's around 20 bags per kg of CO2. We can argue around these figures by altering the weight of each bag, but I don't think the situation is as bad as you infer. There's still a lot of CO2 per bag though.
But when you look at the cost of recycling 1kg of plastic bags? It's less than 1MJ/kg, and the bags are readily recyclable. Carbon cost of producing plastic bags from recycled polyethylene is thus next to nothing, and the material is almost infinitely recyclable.
The next thing to do is look at the carbon cost of producing a re-usable bag from textiles. Which is much larger. Then look at the recycling options available to you, and their cost.

Suddenly, the whole impetus to ban single use plastic bags is a lot less clear cut when you do the lifecycle assessment, especially if you can close the loop and make sure that they are recycled after use. Plastic is actually quite a sustainable material used very unsustainably in the main. Which is not the fault of the material, more the fault of the user of the material.

Recycling of plastic

Some figures about production and recyling of plastic can be found in this comment about plastic.

A recent study (see link above) showed that recycling plastic reduces the carbon footprint of plastic by 2.5 kg CO2 per kilogram of plastic. Using your figure above, the carbon footprint is 2.5 kg CO2 per kg recycled plastic compared to 5 kg CO2 per kg of new plastic. (3.5 kg compared to 6 kg using my own figures, see main article above)

So recycling does about halve the carbon footprint of plastic, but I wouldn't call this carbon footprint "next to nothing".

people should recycle to help

people should recycle to help the earth haha jk lol ! :D

carbon dioxide emission

carbon dioxide emission has caused climatic changes in different biomes around the world

Carbon content of fuel

I almost despaired of finding simple information on this subject against the clock; this is excellent.

carbon footprint calculation for buildings


Do you know how can I calculate carbon footprint for utility(Electricity,Gas,Water) consumption in buildings?


Carbon footprint for electricity and gas

Yes, to calculate the carbon dioxide emissions from electricity and gas, you can use our offline carbon footprint calculator (click on the link to download)

Regards  Juerg



i lov gooners

Thanks a lot


Just wanted to say thank you for this information. I'm currently doing a research project on carbon footprinting and found it helpful.
Also I would like to leave something on this site if its okay. Its a link to a carbon footprint calculator www.carbonfootprint.com/calculator.aspx . I found this really neat and thought that it would be cool to share with others.

Calculate this!

I'm confused. I reuse my plastic containers and bags and recycle those that have worn out..
Those plastic bags I do purchase are made of recycled plastic.
I compost all my organic waste. I drive a fuel efficient car. I use electricity from a nuclear power plant. I burn my paper waste. My computer goes to sleep when it's not in use.

I find it quite amusing that everyone is "going green". I've been doing all the above for over 18 years and now it has become a fad. I don't buy into all the carbon credit bull. I'm just living in a responsible sensible way, and have been all along. It's about time you all caught up.

so, basically you've

so, basically you've actually taken the time to post a comment on this website whose only purpose is to have a go at everyone else and show off how much you're recycling...

Incineracitions big foodprint

The foodprint may be different, when you take recycled materials. For the second use, only the energy for recycling should be regarded. And with good recycling techniques, like kryo- recycling, all materials of the computers, you are just using, could be reused in future several times.
Every good recycling- system avoid the energy- demand for new production. Incineration allways increase new production. So it has a big carbonic foodprint. Its a ferry tale, that you can win "energy from waste".

Felix Staratschek

Plastic Sandwich bags vs. Plastic Sandwich Container

Please tell me the carbon footprint of a package of plastic throw away sandwich bags vs. a plastic sandwich container which can be used over and over again?


Carbon footprint

The carbon dioxide gases in the air are definitely not helping the cause. Since i don't have a car, i would gladly recycle and use things environment friendly. People could car pool, too, to cut down the amount of carbon dioxide roaming the air. We NEED cars to survive, and they are a huge part of the world today. But we can cut down the amount we use these things.

Jamie W. 3rd


I needed to know the definition of a carbon footprint was so I could study for a test and I found it here Thanks!!!

effects of carbon footprint

what are some environmental effects that the average US citizen's carbon footprint is causing? is it causing global warming, depletion of the ozone, etc.?

CO2 for producing an ounce of GOLD

I would like to know if anyone would be able to answer of give me an idea where to find how much CO2 emissions are created to create an ounce of Gold. I would imagine it depends on alot of different variables, such as geography, type of mining operation etc... but If anyone has an idea where to find this information please let me know. You can send an email to jaymantoronto@hotmail.com



I am looking for an emissions calculator for smaller, more specific things such as non recyclable plastics (bags, caps, package wrapping, tape...), bits of metal, aluminum wrappers (from granola bars, etc), bottle caps, tissue...
Do you know of a site that has a calculator for these kinds of things or at least a formula that I can use to make calculations myself?




Contact info would be useful, eh?? ;)

Thanks again!


ur website is the best one iv found to get info for my carbon footprint project! Xp

carbon footprint of buses

This site has some very useful data on measuring the carbon footprint of cars. However, (not being a specialist in the field) one thing is not clear to me- will one liter of petrol or diesel always produce the same amount of CO2 irrespective of the vehicle or are other factors involved? In other words are CO2 reductions in transport only dependant on fuel efficency? So will a really old car release the same Co2 per liter used as a very modern model?

Actually my research involves buses and diesel not cars and petrol but I guess the concept is the same- so any help on this would be very much appreciated !!

CO2 emission of burning 1 liter of petrol

The answer to your question is YES. Burning one liter of petrol always creates the same amount of CO2. It doesn't matter for the CO2-emissions whether an old car or a new car is used.

You can find further details here and here.



Hi how do I cite ur work???

Hi, the data provided in your article is awesome and interesting.
Can I cite it on my website used in my article and if I can than how do I write the citation...? I will use the data indirectly.


Citation information

Thank you for your kind remark. You can find information about citation here.



this information saved my science project!!!!

cradle to grave

your figures don't seem to include the amount of carbon needed to PRODUCE the various fuels. Do you have that data? thanks

Cradle to grave carbon footprint of fuels

No, I don't have that data. It is very difficult to get because it makes a lot of difference from where the fuel is coming from (from the ground or from sand) and where it is getting transported to.

As a rule of thumb for oil from the ground you can estimate as follows:

  • The average energy return on crude oil is about 10:1 (see here). In other words: 10% of the energy content of crude oil is used to get it out of the ground.
  • The refining process to convert crude oil into fuel takes another 10% of the energy content
  • The effect of transportation may not be that important because of the high energy intensity of fuel.

I hope this helps as rough guideline!


very useful information but

very useful information but could have been more better if it would be in a little detail!!!!!

pls answerr my question

i wanna know how many carbonfootprint is produce when making a 1 meter polyethylene-aluminum-polyethylene in a water production pipe

Carbon Footprint

A lot of thanks for all this information cause i had to make a project on this topic and present it to the teacher and the whole class and the shocking part was that i got the hieghest marks for the project in the class i got 36 out of 40 marks for the project

Carbon Footprint :)

I also had to make a project on this subject for my Geography Class. It was out of 50 marks and i was really very shocked because i got 47 in a half out of fifty ! :D ThankYou so much, I guess this site has all the info ! <3


This website is very informative and useful. I used the site for a source in one of my classes. Thanks.

CO2 from production

Do these figures (eg. 2.3 kg CO2 per ltr for petrol) include the carbon release involved in extracting, transporting and processing and wholesaleing/retailing of a litre of petrol/gasoline. Shouldn't it both carbon content and production carbon for a fair assessment of the CO2e pollution from petrol/gasoline? (Any idea what this might be?)

CO2 is only from oxidation (burning)

The above mentioned CO2-emissions have only been calculated for the burning (oxidation) of the fuels. These figures are easy to calculate and quite exact.

You are right that extracting, transporting and processing does also release CO2. However these values are more difficult to assess. You can find some guidelines in the following link:

cradle to grave carbon footprint of fuels

Regards, Juerg



I am Chris Stevens, founder and conceiver of www.WorldTreeProject.com. I found your website searching for other green companies, websites and projects. Please examine our simple website and offer some feedback, provide a link from your website or just remember us for future reference.

Chris Stevens

CO2 weight

How do you actually measure CO2? So far, what I've read about how much co2 is produced is based on what, and how much, was consumed (gasoline, propane, natural gas, diesel, etc). Where does one acquire such a device?

CO2 emission of burning fossile fuels

Calculation of CO2 emissions

Table: Global warming contribution of fuels

Low cost instruments to measure CO2 concentration are usually based on Infrared technology.



thanks i got the answer

awesome webside :)

awesome webside :)