C Level
Flight Carbon Calculator
Enter your departure and arrival airports to calculate the estimated climate impact of your flight in kilograms of CO₂e.
The calculation is free. If you choose, you can then contribute to community-led forest and landscape restoration. The calculation and the contribution are shown separately.
Plan Vivo certified. See the registry →Calculate your flight emissions
The result includes the fuel burned during the flight, the production and delivery of that fuel, the UK Government’s allowance for additional warming effects at altitude and, where the Government publishes one, a cabin-class weighting. It does not model the aircraft used for your particular flight. See exactly what the result includes.
Fund a restoration project for this flight
You can make an optional card payment to support independently verified climate and nature projects.
Fund a restoration projectFor organisations
Using this flight for work?
Request a dated PDF showing the flight’s CO₂e result, calculation method and emission factors. It can be retained for Scope 3, procurement or client reporting.
Calculate the flight above, then tick This flight is for work beside the result.
C Level has worked in carbon and community-led restoration since 2000. We have supported many of the same project organisations for years, and we visit their work on the ground.
The projects we offer are certified under Plan Vivo, which means they are independently validated and verified. See the registry.
The Plan Vivo Standard requires that at least 60% of the revenue from each certificate sale goes to the community carrying out the work.
+Where the rest goes
Plan Vivo requires the project developer to direct at least 60% of the revenue from each Plan Vivo Certificate sale to the local community. The percentage applies to certificate revenue, not to the VAT-inclusive amount paid at checkout.
The community share pays smallholders for the land they manage and the trees they plant and protect. It can also support shared local needs, seeds and planting work.
The remaining certificate revenue pays for the work needed to run and verify the project. This includes project design, local coordinators, staff, equipment, field monitoring, independent validation and verification, communications and sales. A small share also goes to the Plan Vivo Foundation, which maintains the standard. Plan Vivo explains how its model works.
Step 2. Fund a restoration project
For the one-way economy examples on this page, contributions range from about £4 to £21. Return journeys, premium cabins and several passengers cost more because the calculated emissions are higher.
Payment is by card or PayPal through Stripe. C Level never receives your card details. Apple Pay and Google Pay are not currently accepted. Contributions are non-refundable once made.
+Before you pay: what you receive and what happens next
What you receive
A certificate naming the project and the quantity of project carbon benefit supported.
When it arrives
The certificate is issued automatically, usually within fifteen minutes.
If you change your mind
Contributions are non-refundable once made.
If you need help
Contact Daren Howarth at [email protected].
What your flight emissions result includes
The calculator uses UK fleet-average conversion factors. It gives a reproducible estimate for the route and cabin class you enter, but it does not claim to know the aircraft, load or weather conditions on the day.
Scroll the table sideways to see every column →
| Component | Included in the result? | How it is treated |
|---|---|---|
| Direct fuel-burn CO₂ | Yes | Government rate multiplied by distance |
| Cabin-class weighting | Where the Government publishes one | Flights within the UK use one rate for every cabin. For short haul, business and first are 1.5 times economy. For long haul, the weightings are economy 1, premium economy 1.6, business 2.9 and first 4.0 |
| Non-CO₂ effects at altitude | Yes | The UK Government’s central estimate adds 70% to the CO₂ part of the figure. The Government states that the uncertainty is significant |
| Production and delivery of fuel | Yes | Includes extracting, refining and transporting the fuel before it reaches the aircraft |
| Aircraft type | Through fleet averages | The factor represents the average UK fleet. The calculator does not select the aircraft used for your flight |
| Passenger load and belly cargo | Through fleet averages | The factor includes average loading and cargo allocation. The actual load and cargo on your flight are not modelled |
| Indirect routing | Yes | The Government factor already includes an 8% allowance for indirect routes, holding and circling. We do not add it to the distance again |
| Project funding through this page | Never deducted | A contribution is recorded separately from the emissions figure. What funding does and does not do |
The three parts of your result
The total combines direct CO₂ from the flight, the Government’s central estimate for additional warming effects at altitude, and the emissions from producing and delivering the fuel. For long-haul economy, the combined rate is 141.65 g CO₂e per passenger-kilometre.
Scroll the table sideways to see every column →
| Part of the result | Rate, g CO₂e per passenger-km | Share of the total | London to New York, economy, kg CO₂e |
|---|---|---|---|
| Direct CO₂ from burning fuel | 69.26 | 49% | 384.0 |
| Non-CO₂ effects at altitude, including contrails and nitrogen compounds | 47.78 | 34% | 264.9 |
| Producing and delivering the fuel | 24.61 | 17% | 136.5 |
| Total | 141.65 | 100% | 785.4 |
All three rates come from the Government workbook. It publishes the flight rate both with and without the uplift for non-CO₂ effects, so the difference between those two columns gives the non-CO₂ part, and a separate well-to-tank rate covers fuel production and delivery.
An earlier version of this page divided the total the wrong way between these three parts. The components shown here are read directly from the workbook columns. The total rate of 141.65 g never changed, so no calculator result was ever affected by the error.
How the flight carbon calculator works
Distance
The calculator measures the great-circle distance between the airports you enter, using airport coordinates from OpenFlights. Connecting flights are added one leg at a time, and a return journey doubles the distance.
We do not add a separate allowance for indirect routing. The UK Government conversion factor already includes an 8% allowance for flights that do not follow the shortest possible route, including holding and circling. Adding the same allowance to the distance would count it twice.
UK Government emission factors and calculator version
The rates come from the UK Government’s 2026 greenhouse gas conversion factors, published by the Department for Energy Security and Net Zero on 11 June 2026.
Each rate combines two published figures: the flight itself, including the Government’s central uplift for non-CO₂ effects, and the well-to-tank emissions from producing and delivering the fuel. For long-haul economy, the flight rate is 117.04 g and the fuel-supply rate is 24.61 g, producing a total of 141.65 g CO₂e per passenger-kilometre.
The same calculation reproduces all twelve rates the calculator uses. Every result records the factor version it was calculated with.
What this flight estimate cannot show
This is a pre-flight estimate based on fleet averages. Actual emissions will be affected by the aircraft used, the route flown on the day, the weather, the passenger load and the amount of freight carried. The calculator does not have those details, so it does not present the result as the measured emissions of a particular flight.
Flight emissions by route and cabin class
How the calculator classifies each route
The calculator does not classify a flight by its distance. It follows the UK Government table, which classifies routes according to the countries or territories at each end of the journey.
Distance still matters to the underlying fuel use, because take-off accounts for a larger proportion of a short journey than a long one. But distance alone does not determine which Government rate applies.
Scroll the table sideways to see every column →
| Kind of flight | Applies to | Economy rate, g CO₂e per passenger-km |
|---|---|---|
| Within the UK | Both airports are inside the United Kingdom | 262.78 |
| Short haul from the UK | One airport is in the UK and the other is in a country the Government lists as short haul, covering most of Europe and North Africa | 148.25 |
| Long haul from the UK | One airport is in the UK and the other is in a country the Government lists as long haul | 141.65 |
| Between two countries outside the UK | Neither airport is in the United Kingdom | 125.72 |
Until 14 August 2026 the calculator treated any flight of 600 km or less as a flight within the UK. The Government factors contain no such rule, and the mistake charged London to Paris at the UK domestic rate, which was 77% too high. The calculator now follows the Government’s country classification.
The Government’s own table shows why distance cannot be the rule. It lists Moldova as long haul and Turkey as short haul, even though Turkey is further from London.
The Government table does not include 19 territories for which the calculator has airports. They are in the Caribbean, Pacific, Indian Ocean and South Asia. We classify them as long haul, because every comparable territory in the Government table is long haul. This is C Level’s judgement rather than a published Government classification, and the result says so when it has been used.
Cabin class
A premium seat occupies more space, so a larger share of the aircraft’s emissions is allocated to it. The calculator uses the UK Government’s published 2026 cabin-class factors.
For flights within the United Kingdom, the Government publishes one rate and does not distinguish between cabins, so every cabin produces the same result.
For short-haul flights, the Government publishes economy and business rates only. The calculator uses the economy rate for premium economy and the business rate for first class, and says so when it has done that.
For long-haul flights and journeys between two countries outside the United Kingdom, the Government publishes all four cabin classes. The weightings are economy 1, premium economy 1.6, business 2.9 and first 4.0.
Worked flight-emissions examples
These examples use the 2026 factor set and were calculated on 14 August 2026. Each is for one passenger travelling one way in economy unless the row says otherwise.
Scroll the table sideways to see every column →
| Route | Distance, km | Emissions, kg CO₂e | Contribution excluding VAT, £ |
|---|---|---|---|
| London Heathrow to Edinburgh | 534.03 | 140.33 | 3.68 |
| London Heathrow to Madrid | 1,244.86 | 184.55 | 4.84 |
| London Heathrow to New York JFK | 5,544.61 | 785.39 | 20.62 |
| London Heathrow to New York JFK, business class | 5,544.61 | 2,277.56 | 59.79 |
Why flight carbon calculators give different results
Flight carbon calculators use different data and draw different boundaries around the journey. Two calculators can therefore produce different figures without either calculation containing an arithmetic error.
Scroll the table sideways to see every column →
| Calculator or method | Flight data used | Cabin class | Fuel production and delivery | Non-CO₂ effects at altitude |
|---|---|---|---|---|
| C Level (this page) | The countries at each end of the route | Yes, wherever the Government publishes a cabin-specific rate | Included | Included, using the Government’s central 1.7 multiplier |
| ICAO ICEC | Route and scheduled aircraft mix | Yes | Not included | Not included |
| IATA RP1726 / CO2 Connect | Airline operational data | Yes | Not included | Not included |
| UK DESNZ conversion factors | Haul and cabin averages | Yes | Published as separate factors | Published as a separate 1.7 uplift |
The treatment of non-CO₂ warming effects is one of the largest sources of disagreement. Contrails and nitrogen compounds released at altitude affect the climate, but there is no agreed multiplier that every calculator uses. The UK Government recommends 1.7 as a central estimate and describes the uncertainty as significant. ICAO excludes an uplift because there is no scientific consensus on a single value, IATA applies none, and some other calculators use a multiplier of 3.
When you are comparing calculator results, check whether each figure includes fuel production, cabin class and non-CO₂ effects before deciding that one of them must be wrong.
Flight emissions for business travel and Scope 3 reporting
Business air travel sits in category 6 of Scope 3 under the GHG Protocol. A company recording its flight emissions needs to retain the result, the conversion factors and the calculation method, rather than relying on an unexplained total.
Some organisations use the calculator for one journey. Others need to work through a year of travel for a company, department or production.
Flights are only one part of a company footprint. C Level’s business carbon footprint calculator covers Scope 1, Scope 2 and common Scope 3 sources using the same UK Government factors. It is free and does not require an account.
Business flight emissions report
You can request a dated PDF for the flight you calculate. The report records the CO₂e result, factor source, calculation method and version.
Calculate the flight at the top of this page and tick This flight is for work under the result. Enter your work email and organisation name, and the report will be sent automatically. You do not need to make a project contribution to receive it.
The report is requested beside the result because it records the details of that particular flight.
Work out a flightWorking with procurement
C Level works with organisations that measure and report their travel emissions and choose to support community-led climate and nature projects. We have worked directly with Plan Vivo project organisations since 2000.
If you need an invoice, select Pay by invoice instead of card beside the result. Payment is due within 30 days and there is no minimum contribution. Requesting a business report and choosing a payment method are separate steps. You can receive the report without contributing, or receive it and still pay by card.
C Level Earth Limited is registered in England and Wales under company number 04105851. Its registered office is at the Innovation Centre, Brighton, BN1 9SB. VAT registration number: 890003646.
Funding a climate project for your flight
Once you have your result, you can choose to fund a community-led restoration project. This section explains what that contribution does, what it costs and which projects it reaches.
What funding does and does not do
Funding a restoration project does not reduce the emissions figure your organisation reports. It is a contribution alongside reducing that figure, not instead of it.
Project funding pays for forest and landscape restoration and supports the communities carrying out the work. It does not undo the flight or change the emissions figure this calculator produced, and we will not tell you that it does.
That separation is also how the accounting works. Under the GHG Protocol, purchased credits and project-based reductions are reported separately from a company’s Scope 1, Scope 2 and Scope 3 inventory, and are not deducted from it. See the GHG Protocol Scope 3 FAQ and the Land Sector and Removals Guidance.
If a journey can reasonably be avoided, not taking it will reduce emissions in a way that funding a project cannot. A contribution is an additional action for the flights that still take place, not an alternative to flying less.
What the money buys is real work in a named place. Your contribution supports activities assessed under Plan Vivo’s additionality requirements, and the benefit those activities produce is measured and verified in its own right.
What it costs
The contribution is priced at £26.25 per tonne of CO₂e, plus VAT. For a one-way economy flight, the examples on this page cost £3.68 from London to Edinburgh, £4.84 from London to Madrid and £20.62 from London to New York. The checkout shows the contribution and VAT separately before payment.
Carbon credits are sold at a wide range of prices. Ecosystem Marketplace reported average 2024 prices of about US$6 per tonne for avoided-deforestation credits and about US$20 per tonne for planting and restoration credits. Those averages do not establish the quality of an individual project, or show how much of the money reaches the people doing the work.
C Level’s £26.25 rate supports long-term community-led restoration certified under Plan Vivo. The price reflects the work required to establish, monitor and verify the projects, and to pay participating communities over time.
Where the money goes
C Level has long-term working relationships with the project organisations below. Each project explains how the land is managed, what carbon outcome it produces and how the work is monitored.
Those outcomes are not interchangeable, so each project says which one it produces. Removal takes carbon dioxide out of the atmosphere. Reduction lowers emissions that would otherwise occur. Avoidance prevents expected emissions from being released.
CommuniTree, Nicaragua
CommuniTree pays smallholder farmers in northern Nicaragua over ten years to plant and tend native species on degraded land. Payments are released in stages and are linked to monitoring, rather than paid entirely at the beginning.
This project produces removals. The trees take carbon dioxide out of the atmosphere and store carbon in wood and soil. Plan Vivo verifies the outcome, and the staged payments support farmers as the trees become established.
Plan Vivo Standard, project PV_2011_005. See the registry.
Read about CommuniTree
Mongolian Nomads, Mongolia
The Pastures, Conservation, Climate Action project works with nomadic herders across three sites to restore traditional rotational grazing and reduce pressure on degraded grassland. A total of 116 households take part.
This project produces removals. Recovering grassland draws carbon back into its vegetation and soils. The Mongolian Society for Range Management has coordinated the project since 2013, and it reports its progress every year under Plan Vivo.
Plan Vivo Standard, the Pastures, Conservation, Climate Action project. See the project record.
Read about Mongolian Nomads
Khasi Hills, India
The Khasi Hills project supports community-governed restoration of sacred forest in Meghalaya, through traditional Khasi governance structures.
This project produces both avoidance and removals. Protecting standing forest avoids the release of carbon already stored there, and letting degraded forest recover takes additional carbon dioxide out of the atmosphere. The community monitors the forest and reports progress under Plan Vivo.
Plan Vivo Standard, project PV_2012_009. See the registry.
Read about Khasi HillsAbout C Level
C Level has financed community-led forest and landscape restoration since 2000. We work directly with project organisations, often over many years, and we visit the projects and the communities carrying out the work. Those relationships are the basis of the project information on this page.
We also publish the calculator’s method, the source of its factors and the limits of the result, so you can see what the figure represents before you decide whether to use it. See C Level’s projects.
Flight carbon calculator FAQs
+How much carbon does a flight produce?
The emissions from a flight depend on the route and cabin class. Using the 2026 UK Government factors, one passenger flying one way in economy produces approximately 140 kg CO₂e from London to Edinburgh, 185 kg from London to Madrid and 785 kg from London to New York. London to New York in business class produces approximately 2,277 kg.
Enter your route in the calculator for an estimate based on the airports and cabin you choose.
+How much CO₂ does one passenger produce on a flight?
Every result on this page is calculated for one passenger. The Government conversion factor already allocates fleet-average emissions per passenger-kilometre, and the calculator multiplies that rate by the distance travelled.
For one passenger travelling one way in economy, the examples are 140 kg CO₂e from London to Edinburgh, 185 kg from London to Madrid and 785 kg from London to New York. Multiply the result by the number of people travelling when you are calculating emissions for a family or a team.
+How much difference does economy or business class make?
For a long-haul flight, the UK Government business-class factor is 2.9 times the economy factor, because a business-class seat occupies more space. London to New York therefore produces approximately 785 kg CO₂e in economy and 2,277 kg in business class. Premium economy is 1.6 times economy and first class is 4 times economy on long-haul routes.
The treatment differs for other routes. On short-haul flights, premium economy uses the economy rate, while business and first use a rate 1.5 times higher. Flights within the United Kingdom use the same rate for every cabin, because the Government does not publish cabin-specific domestic factors.
+How does the calculator handle a return flight or connections?
A return journey doubles the distance and therefore approximately doubles the emissions result.
Connecting flights are calculated one leg at a time, which is different from measuring the direct distance between the first departure airport and the final destination. Each leg is classified separately, so one journey can include both a domestic and a long-haul rate. A connection may also increase the result, because take-off accounts for a greater share of fuel use on a short leg.
+How does the calculator calculate flight emissions?
The calculator multiplies the great-circle distance between the airports by the appropriate UK Government rate for the countries and cabin class you enter. It adds connecting legs separately and doubles the distance for a return journey.
The result includes direct CO₂, the Government’s central allowance for non-CO₂ effects, and the production and delivery of aviation fuel. It does not model the particular aircraft, passenger load or freight carried on the day.
+What does it mean to offset a flight?
Offsetting generally means funding a climate project to compensate for emissions produced elsewhere. The project benefit is measured and verified in its own right, separately from the emissions of the flight.
What funding does and does not do sets out what that means in practice.
+What other benefits can project funding support?
Depending on the project, funding can support forest and habitat restoration, biodiversity, soil and water systems, livelihoods and resilience to climate change. The projects offered here are certified under Plan Vivo, which requires independent validation and verification.
+How much does it cost?
The contribution costs £26.25 per tonne of CO₂e, plus VAT. For the worked examples above, this is £3.68 for London to Edinburgh, £4.84 for London to Madrid and £20.62 for London to New York in economy. The checkout shows the contribution and VAT separately before payment.
+Why does this result differ from my airline’s figure?
The figures may use different calculation boundaries. Airlines and industry bodies often report direct CO₂ from burning fuel, while other calculators also include fuel production or the additional warming effects of aviation at altitude. Cabin-class treatment and aircraft data can also differ.
The comparison table above shows which elements are included in the C Level, ICAO, IATA and UK Government approaches.
+What is radiative forcing, and is it included?
Burning aviation fuel releases carbon dioxide, but aircraft also produce contrails and nitrogen compounds at altitude. These have an additional warming effect, often described in flight calculators as radiative forcing or the non-CO₂ effect.
The C Level result includes the UK Government’s central estimate, which adds 70% to the direct CO₂ part of the figure. The Government states that the uncertainty is significant. Its uplift applies to the complete flight rather than only to the part flown at altitude.
There is broad agreement that these effects matter, but no agreement on one multiplier. The UK Government uses 1.7 as its central estimate, IATA applies no uplift, ICAO excludes one because there is no scientific consensus on a single value, and some calculators use 3.
+Can I use this calculator for Scope 3 business travel reporting?
Yes, as an estimate. Business air travel is category 6 of Scope 3 under the GHG Protocol. The calculator uses the UK Government’s 2026 conversion factors and records the method and factor version used for the result.
You can request a dated PDF containing the flight details, CO₂e result, factors and method. If you also fund a project, record that contribution separately from your inventory. What funding does and does not do explains why.
Use the flight carbon calculator on your website
Publishers, universities and charities can embed the calculator free with one line of code and no account. Travel, event and film companies can also discuss running the calculation inside their own booking or reporting systems through the C Level API.