No questions, no waiting. Cover the average UK footprint for one person for one year, or scale it up for everyone in your home. A reasonable estimate if you'd simply rather act now than work out your own number.
A few quick questions about home energy, driving and flights, no bills needed. A real estimate, personal to you, in about the time it takes to read this card.
Bills, mileage, travel and spend. For individuals and households who want a precise, auditable number, not just a good estimate.
UK average taken as 10 tonnes CO₂e per person per year (not per household), consumption-based, 2023 — Defra official statistics. Household figures treat about a quarter of the average as the home itself, shared by everyone living there, so each extra person adds around three quarters of the single figure rather than the whole again. UK average from Defra; other countries from OECD (2022), Greenhouse gas footprint indicators, accessed September 2026, CC BY 4.0, same basis, rounded to the nearest tonne. Your country is suggested from your device's time zone and can be changed above; if yours is not one of the 80 we cover, UK figures are shown. Home energy in the quick calc uses your country's 2026 grid electricity factor from CaDI, Carbon Footprint Ltd's own carbon database and the same factors the full calculator applies.
Sustrax Vita is our personal carbon footprint calculator for individuals and households, and no account is needed. Enter your home energy, travel and lifestyle details and get your full result straight away, then come back each year to compare. Try it here, or read on below to see exactly what it measures and how the numbers are worked out.
Five areas of everyday life, added together into one annual figure in tonnes of CO2e. A few questions on each is all the full calculator above needs.
Enter electricity and gas from your bills, in kWh or pounds, plus any oil, LPG, coal or wood.
Usually the largest slice of a UK footprint. The calculator applies the grid factor to electricity and a fuel-specific factor to the rest, then shares the total across everyone in your home.
Enter your departure and arrival airports and the class you flew.
The calculator works out the distance, applies the short-haul or long-haul factor and adds the extra warming effect of emissions at altitude. One long-haul return can outweigh a year of driving.
Enter your annual mileage and vehicle type, or the exact make and model.
Petrol, diesel, hybrid, plug-in hybrid and electric each have their own factor. Electric vehicles count the grid electricity used to charge them rather than scoring zero.
Enter the miles you travel by bus, coach, rail, Underground, tram, ferry and taxi.
Each mode has its own factor per passenger mile, so a busy commuter train comes out far lower per person than a taxi on the same route.
Answer a handful of spending questions on food and drink, clothes, electronics, furniture, leisure and services.
The secondary footprint: the emissions embedded in what you buy, estimated with national spend-based factors. The hardest part to measure and often a third of the total.
The calculator runs on Sustrax, the carbon accounting platform Carbon Footprint Ltd builds for businesses. Your personal figure uses the same calculation engine and the same emission factors as a company's audited footprint, so it is a credible number rather than a rough guess.
Emission factors come from the UK Government's annual greenhouse gas conversion factors, published by the Department for Energy Security and Net Zero (DESNZ). The factor year is matched to the year your data covers, so 2026 activity is calculated with the 2026 factor set. Results cover all the main greenhouse gases, not only carbon dioxide, and are reported in tonnes of CO2e.
Burning a litre of petrol or a unit of gas is only part of its footprint. Extracting, refining and delivering that fuel also releases greenhouse gases, and electricity loses energy in transmission and distribution before it reaches your meter. These well-to-tank and grid-loss emissions are included in your total. Leaving them out would understate most fuels by around a fifth.
Aircraft emissions at cruising altitude have a greater warming effect than the same emissions released at ground level. DESNZ publishes an uplift for this, known as radiative forcing, and the calculator applies it to every flight by default. Some calculators leave it out, which is one reason flight figures vary so much between tools.
If you live elsewhere, your electricity is calculated with the grid factor for your country from our CaDI database, which covers generation, grid losses and well-to-tank emissions where the data exists. See our international electricity factors and the international factors methodology.
For a category-by-category explanation of the Sustrax methodology, including how each input is converted into emissions, read the calculator FAQs.
A footprint on its own is just a figure. These four reference points turn it into something you can act on.
The national figure counts everything the country consumes, including public services and infrastructure, so your calculator result will usually come out lower: it covers what you control directly, your home, your travel and your spending. Frequent long-haul flights, a lot of driving or a large gas-heated home push it up. A flat, little flying and public transport bring it down. The point is not the exact decimal but knowing which one or two areas dominate your result, because that is where the biggest reductions are available.
The full calculator above keeps your entries year on year, so you can watch the number fall as you change how you heat, travel and shop.
Reduction always comes first. These four changes make the biggest difference for most UK households.
Practical answers about your footprint, country figures and the difference between a quick estimate and the full calculator.
Yes. The carbon footprint calculator has been free to use since Carbon Footprint Ltd launched it in 2005, and it still is. There is no charge for the quick calc or for the full calculator, and no card details are asked for at any point.
No. Both the quick calc and the full Sustrax Vita calculator work without an account. You only need one for the business calculator, Sustrax Lite, or to complete a purchase when you buy carbon credits in the marketplace.
Use the Cover stepper on the Just cover it card to add everyone who lives with you. We do not ask you to split adults from children. The home itself, its heating, power and upkeep, is about a quarter of an average footprint and is shared by everyone living there, so each extra person adds around three quarters of the single-person figure rather than the whole again. That already brings a family's figure well below a straight multiple. Research suggests a young child's footprint is roughly half an adult's, but the evidence is not firm enough to build into a quick figure, so we keep it simple: one count, one price. If you want a precise household number, the full calculator asks about each person's travel and lifestyle.
The UK average is Defra's official consumption-based carbon footprint per person, produced with the University of Leeds and the Office for National Statistics, for 2023. For other countries we use OECD (2022), Greenhouse gas footprint indicators, published under CC BY 4.0, which measure the same thing on the same basis: everything a resident's spending causes, including emissions embedded in imports. Both are rounded to the nearest tonne. Your country is suggested from your device's time zone, so nothing about you is sent anywhere, and you can change it using the selector under the three options. We cover 80 countries; if yours is not one of them you will see the UK figures. In the quick calc, the electricity part of your home energy uses your country's 2026 grid factor from CaDI, the Carbon Database Initiative, which is our own free-to-use database and the same source the full calculator draws on.
The quick calc estimates your home energy from the size of your home and how it is heated, using your country's grid electricity factor from CaDI, and uses national averages for everything else it does not ask about. Its allowance for goods and services scales with your country's average, and driving, flights and food are counted as they are. Treat it as a rough guide rather than a measurement. It is good enough to see roughly where you stand and to take action straight away. For an accurate figure, use the full calculator above with your actual bills and mileage.
All three names describe the same tool. A carbon footprint calculator, carbon calculator, CO2 calculator or carbon emissions calculator all work out the greenhouse gases your activities cause and express them as tonnes of CO2e. Ours has done that for individuals since 2005, and the free business version, Sustrax Lite, does the same for a company.
Both. It was built in the UK and uses UK Government factors, so it is the most established free carbon footprint calculator for UK households. It also works anywhere else: the full calculator applies your own country's electricity grid factor, and the quick calc and the average figures switch to your country automatically, with a selector to correct it.
CO2e stands for carbon dioxide equivalent. Activities release several greenhouse gases, including methane and nitrous oxide, each with a different warming effect. CO2e converts them all into the amount of carbon dioxide that would cause the same warming, so a single figure can describe your whole footprint.
Yes. The full calculator keeps your entries, so you can return, update your figures and see how your footprint has changed since you last measured it. That is the best way to check whether the changes you make are working.
Two paths to start measuring your company's impact: try our free SME calculator, or bring in our experts for a hands-on assessment.
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