Add a journey

The TCW Carbon Calculator allows you to calculate the greenhouse gas emissions of your travel. You can input multiple journeys using a variety of modes of transport.

To begin using the calculator:

  • Start typing the origin city of your journey into the first box.
  • As you type, a list of world cities will appear. From this list you can choose the correct city.
  • Select the mode of transport you will be using and tick the box if you are making a return journey. If you choose a journey via car you can additionally select the number of passengers so the carbon emitted is shared amongst them.
  • To add a follow-on journey from your destination click the 'Follow-on' button or to add an additional separate journey click the 'New' button.
  • Once you have filled in your journey's details, the distance and CO2 emissions will then be calculated automatically.
  • If you want to change the start, destination or mode of transport, hover over it until you see the cross appear then click to show the selection box again.
  • To begin a new set of journeys click 'Reset' to clear your last journey's details.

Once you have added all of your journeys you can click 'explain' to get more details about the CO2 emissions of your travel.

You can choose to donate to The Converging World in acknowledgement of these emissions. We have suggested a donation of £10 per tonne (you are free to lower or raise the level of the donation), which will be use in our programmes. Please note that when we invest money into renewable energy, we generate long term funding for more social and environmental initiatives including reforestation.

TCW's carbon calculator allows travellers to evaluate the level of greenhouse gas emissions associated with their travel and support TCW's work in addressing climate change, through renewable energy, reforestation and sustainable livelihoods. For more information about our programmes please visit www.theconvergingworld.org/what_we_do

The calculator was developed in partnership with ethical travel resource Much Better Adventures. Its aim is to provide a relatively accurate and flexible means of assessing the greenhouse gas emissions associated with travel. The other tabs above give information about the work of TCW, the methodology used in the calculations, information about how your donations will be used and the kind of projects they will support. We intend complete transparency in our calculations and if you need further details than are provided in this information box, please get in contact with us: info@theconvergingworld.org

This carbon calculator allows you to evaluate the carbon footprint of your travel. By taking into account factors including distance travelled, mode of transport used and number of passengers travelling, it is possible to calculate the levels of greenhouse gasses that your journey produces. Our calculator uses values for calculating greenhouse gas emission based around the DEFRA's Guidelines for GHG conversion factors, these are available to download here.

The values are expressed in masses of CO2 equivalent. CO2 is the primary greenhouse gas associated with travel but we have taken into account other gasses and converting them to CO2 masses based on their global warming potential.

Explained in more depth below are the principles upon which The Converging World's travel calculator calculates your journey's emissions.


Distances are calculated using the spherical law of cosines:

d = acos(sin(lat1) x sin(lat2) + cos(lat1) x cos(lat2) x cos(long2-long1)) x R

Where R is the radius of the earth (rounded to 6371 km) and lat1,long1 are the latitude and longitude of the journey origin converted from degrees to radians and lat2,lon2 are those of the destination. It assumes a straight line journey for simplicity which is reasonably accurate for flights but may not be for overland journeys. It may be more accurate to calculate the distance by inputting a number of sub-journeys (i.e. breaking the journey down into major way-points).


The calculator uses the following values for calculating greehouse gas emissions. These are based around DEFRA's Guidelines for GHG conversion factors available to download here.


CO2 = d x sos x cor x rf x cf
d = distance in km
sos = 1.09 (factor for sub-optimal routing and stacking)
cor = 1.1 (CORINAIR uplift for descent/takeoff)
rf = 1.9 (factor for radiative forcing, NOX, water vapour)
cf = conversion factor for selected cabin class and distance band.
Please see DEFRA document for further details.


CO2 = d x cf
For simplicity the DEFRA conversion factor (cf) for small and medium vehicles has been combined, leaving normal and large categories. Petrol and Diesel factors have also be combined proportionally based on percentage of diesel vehicles in use in the UK. We have included the option to choose the number of passengers as sharing significantly affects the results for this mode of transport (dividing my 2, 4 etc) whereas the number of passengers for other modes of transport is harder to measure and generally beyond your control.


CO2 = d x cf
DEFRA conversion factors (cf) for average bus travel and coach travel are used.


CO2 = d x cf
DEFRA conversion factors (cf) for foot and car passengers are used as these vary significantly.


CO2 = d x cf
DEFRA conversion factors (cf) for national rail and Eurostar are provided.

For more details, please see the DEFRA document linked above or contact us.

Our vision: to converge toward one planet living for the wellbeing of all communities.

We invest in renewable energy to create long-term funding streams that enable and support social and environmental projects. Security of energy supply, affordability and dirty grids are a worldwide problem. Addressing these issues by installing clean energy sources are part of our mission and help generate long-term funding streams for other social and environmental action including reforestation.

For more information about our programmes please visit www.theconvergingworld.org/what_we_do

TCW's work incorporates three key aims: to implement renewable energy; to support communities around the world adapt to climate change, in ways that reduce global inequalities; and to reduce CO2 emissions across the planet. Your donations fund a variety of projects designed to achieve these aims by connecting people all over the world. By donating to TCW you therefore become a key player in addressing global issues and creating a more equitable and sustainable world for all.

TCW projects that your donations will support include:

  • Renewable energy through wind power
  • Ecological restoration
  • Access to affordable sustainable energy
  • Global citizenship

Renewable energy through wind power

Your donations play a major part in funding renewable energy projects in the developing world. These projects generate clean energy which can be sold back into the regional grid for profit. These profits can then be reinvested into the expansion of further renewable energy schemes, as well as into sustainable development projects across the globe. Your donations therefore continue to deliver their effects long after their initial investment into a renewable energy project. We currently have eight wind turbines in the Tamil Nadu district in Southern India. We have installed 12.9 MW and have generated nearly 50 million kWhs and avoided nearly 45,000 tonnes of CO2 (by March 2015). With your help we hope to replicate similar scale projects in other areas of India and also in Africa and South America in the future.

For more information about our programmes please visit www.theconvergingworld.org/what_we_do

Ecological restoration

The world depends upon biodiversity to sustain us. Forests provide the oxygen we need to breathe, control our climate, provide medicines and sustain the livelihoods of millions of people. Over 80% of our forests have now been destroyed. We are working with partners to restore tropical dry evergreen forest to sustain biodiversity and help support livelihoods for people earning less than $2 a day through forest planting and management, and creating medicinal products for resale.

Access to affordable sustainable energy

Poverty and access to affordable energy are inextricably linked. Globally over 1.3 billion people are without access to electricity and 2.7 billion people are without clean cooking facilities. More than 350 million people in India are still without access to electricity. Providing sustainable and affordable options will help some of the most marginalised lift themselves out of poverty whilst preventing environmental damage from less sustainable energy sources.

Global citizenship

We believe that at the heart of any environmental conservation or poverty alleviation programme must be a community which is enabled and empowered to help themselves in organising their own futures whilst recognising the impact of local decisions on the global community. 'Think Global; Act Local' is a core principal underpinning all our work.

To keep up to date with the projects we are working on and the progress we are making as a whole, visit our website www.theconvergingworld.org and sign up to our newsletter.

Because we need to reduce CO2 and avoid emitting it where possible. Whether you choose to donate with us or support these reductions in another way, it is critical that something is done. We want to facilitate an easy way for you to address your CO2 by providing this tool. And we also recognise the need for immediate action. That is why we are dedicated to supporting programmes that address climate change and support community resilience by engaging them in a range or income generating initiatives such are reforestation and renewable energy.

Traveling by plane, car, ferry or bus produces greenhouse gases including carbon dioxide (CO2). Most scientists agree that increasing levels of greenhouse gases in the atmosphere will result in a rise in the Earth's surface temperatures. While this may sound like a great opportunity to reach for the sun-cream and enjoy a few extra sunny days throughout the year, the issue is far more serious.

Increasing temperatures can result in huge and potentially devastating impacts in many vital sectors. Global temperature increases are already having an impact on agricultural activities, sea levels are rising and many areas will become uninhabitable, extreme weather conditions are resulting in droughts and floods more frequently and leading to the increased spread of disease in some areas and costs associated with damage and repair to infrastructure. This greenhouse effect has the potential to cause major problems for the environment, animals and humans alike.

The Converging World works to ensure that high standards and genuine transparency are found in both their offsetting and donation methods. TCW aims to ensure that people do not regard offsetting or donating as an excuse to retain a business-as-usual outlook.

Q: How do you account for the fact that your calculator gives higher/lower CO2 quantities than others?

A: Other calculators are likely to use different methodologies for calculating CO2. These are often simplified and do not include all relevant factors. We have used DEFRA-published figures and tried to be as thorough as possible without making the user-experience too complex.

Q: Why have you chosen £10 per tonne of CO2 as a suggested donation?

A: £10 has been chosen as, what we believe is, a fair amount to donate in recognition of your emissions. We have tried to achieve a balance in not putting people off by asking to much and not asking too little and making the donation trivial. You are of course welcome to change the value of your donation when redirected to TCW's donate page.

Q: Am I offsetting the carbon associated with my flight?

A: No. You are making a donation to The Converging World charity which is broadly in line with the greenhouse-gas emissions of your travel. The Converging World also sells high-quality certified carbon credits - please contact us for more information.

Q: Who/What is The Converging World (TCW)?

A: You can read all about us in the relevant tab of this about box. Our website contains further details.

Q: How will you spend my donation?

A: Our method goes beyond cancelling out an individual's own emissions. TCW invests donations in renewable energy projects - at this time wind turbines in Southern India. The profits generated from these turbines are used to fund development and carbon reduction work at home and abroad. We also reinvest some of the profits in further turbines to ensure the project grows. The benefits of donations made to TCW, therefore, can be felt far and wide and assist in the development of sustainable carbon reducing efforts globally. We may also use them in the reforestation work and other related programmes.