Carbon footprint calculator: estimate yours in 2 minutes

Estimate your carbon footprint in two minutes

The average person on Earth is responsible for about 4.7 tonnes of fossil CO₂ a year, but that average hides a huge spread: about 14.2 t in the United States, 4.5 t in the UK and 2.2 t in India. To stay in line with the 1.5 °C goal, lifestyle footprints need to fall to roughly 2–2.5 t CO₂e per person by 2030.

Fill in the calculator below with your own numbers. It updates as you type, shows which category dominates and suggests the three changes that would cut your footprint most. Your bills give the most accurate kWh figures, but the defaults are sensible starting points.

What is a carbon footprint?

A carbon footprint is the total greenhouse gas emitted because of what you do and buy in a year, expressed in tonnes of CO₂ equivalent (CO₂e). Methane and nitrous oxide, which matter a lot for food and flights, are converted into the amount of CO₂ that would cause the same warming over 100 years.

It has two parts. Direct emissions come from fuel you burn yourself: petrol in your car, gas in your boiler. Indirect emissions happen elsewhere on your behalf: at the power station that makes your electricity, on the farm that grows your food and in the factory that made your phone.

What is the average carbon footprint per person?

Measured as fossil CO₂ produced within each country, the world average was 4.7 t per person in 2024, according to the Global Carbon Project data published by Our World in Data. Countries with large homes, long car journeys and fossil-heavy power grids sit three to four times higher.

You can compare any other country in the CO₂ emissions by country ranking.

A lifestyle (consumption-based) footprint, which includes all greenhouse gases and the emissions embedded in imports, gives a fuller picture. The Hot or Cool Institute estimates about 8.5 t CO₂e a year for a typical UK resident, nearly twice the UK’s production-based 4.5 t. Earlier work by IGES and Aalto University found 10.4 t in Finland, 7.6 t in Japan, 4.3 t in China, 2.8 t in Brazil and 2.0 t in India.

What footprint should you aim for?

The UN Environment Programme’s Emissions Gap Report 2020 says meeting the 1.5 °C goal requires lifestyle footprints of around 2–2.5 t CO₂e per person by 2030. The 1.5-Degree Lifestyles research sets the path beyond that at 1.4 t by 2040 and 0.7 t by 2050. The calculator compares your result with the 2.5 t figure for 2030.

That is a steep drop for most people in rich countries, and much of it depends on cleaner power grids, transport and buildings, not personal choices alone. The IPCC finds that global greenhouse gas emissions need to fall by about 43% from 2019 levels by 2030 to keep 1.5 °C within reach.

What makes up a typical carbon footprint?

Across the countries studied in the 1.5-Degree Lifestyles research, three areas make up roughly 75% of a lifestyle footprint: food, housing (heating and electricity) and personal transport. Goods, leisure and services make up the rest.

• Transport: driving 12,000 km a year in an average petrol car emits about 2.0 t CO₂e. One long-haul return flight adds about 1.6 t.
• Home energy: a typical UK gas-heated home burns about 11,500 kWh of gas, or about 2.1 t CO₂e a year, shared between the people who live there. Electricity depends heavily on the grid: 3,000 kWh is about 0.4 t in the UK but 1.4 t on the world-average grid.
• Food: UK diets range from about 2.6 t CO₂e a year for high meat-eaters to about 1.1 t for vegans. A 2023 follow-up study of 55,504 people found vegans’ dietary emissions were about a quarter of high meat-eaters’.
• Shopping and services: clothes, electronics, furniture, insurance, eating out and the rest. Usually around a quarter of the total and the hardest part to measure.

The biggest single items are usually flights and car use. That is why two households with similar incomes can end up with very different footprints.

How the calculator works

Each answer is multiplied by an emission factor and the results are added up. Home electricity and heating are divided by the number of people in your home. All factors come from the most recent sources we could verify.

A few choices are worth knowing about:

• Flights include radiative forcing. Contrails and nitrogen oxides at altitude add warming beyond the CO₂ itself. The UK government publishes factors with and without this effect; leaving it out would cut flight emissions by roughly 40%.
• Diet figures are the UK study’s kg CO₂e per 2,000 kcal per day (7.19 for high meat-eaters down to 2.89 for vegans), multiplied by 365.
• Electric cars are counted on electricity use only. Including battery manufacturing, the ICCT estimates a battery-electric car on the EU average grid at about 63 g CO₂e per km over its life, still far below a petrol car.
• Shopping and other is set so that “medium” (2 t) is about a quarter of the UK’s 8.5 t lifestyle footprint, matching the share outside food, housing and transport. Low and high are round numbers either side. Treat this line as the least precise.
• Suggestions use the same factors. Heating savings use the IEA’s estimate that each 1 °C lower saves about 7% of heating energy and Nesta’s estimate that a 60 °C boiler flow temperature saves about 9% of gas.

Why carbon footprint calculators give different answers

Run your details through three calculators and you will probably get three different numbers. That does not mean any of them is wrong. They usually differ in four ways:

1. Scope. Some count only CO₂ from energy, others all greenhouse gases plus the emissions embedded in everything you buy. Consumption-based results are higher in rich countries.
2. Emission factors and their vintage. The UK government’s 2025 flight factors fell by between 16% and 42% compared with 2024, because the 2024 set used 2021 data when half-empty planes inflated emissions per passenger.
3. Electricity location. A kWh is about 126 g CO₂ in the UK and 458 g on the world-average grid. A calculator that uses a national average for a different country can be out by a factor of three.
4. Shopping estimates. Most tools convert spending into emissions with average factors per pound or dollar. That is a reasonable guide to scale, but it cannot tell a second-hand sofa from a new one.

How to use your result

Start with the largest bar in your breakdown. Small habits matter far less than a few big decisions, and the research is consistent about which ones those are. A 2020 review of 53 studies by Ivanova and colleagues ranked these among the most effective consumption changes:

• Fly less: dropping one long return flight saves a median of more than 1.7 t CO₂e.
• Switch to renewable electricity: a median saving of 1.6 t CO₂e per person, depending on your grid.
• Live car-free or switch to an electric car: among the top transport options in the review.
• Eat a vegan or mostly plant-based diet: a median saving of about 0.8 t CO₂e.

Once the big items are covered, quicker changes still help, particularly on heating. Our guide to 15 quick ways to reduce your carbon footprint ranks them by how much they actually save.

Then come back in a year and run the same numbers again. Tracking your own trend is more meaningful than any single result.