The Carbon Footprint Calculator estimates the carbon dioxide (CO2) emissions of your car or motorbike based on three things you already know: how far you travel, what fuel or energy it uses, and how efficiently it burns that fuel or uses that energy. Because each litre of fuel releases a fixed amount of CO2 when burned, your emissions can be derived directly from your driving and consumption figures.

You enter a distance and how often you travel it, pick a fuel type (petrol, diesel, LPG, electric or hybrid), and type in your vehicle's consumption in litres per 100 km (or kWh per 100 km for electric cars). The tool then works out your daily, weekly, monthly and yearly CO2 output, the total fuel or energy you use each year, an optional yearly fuel cost, your footprint per person when you car-share, and how many trees would be needed to offset your annual emissions. A clear line-by-line breakdown shows exactly how each number was reached, and every emission factor is editable so the results reflect your region and fuel blend.

It is useful because transport is one of the largest everyday sources of CO2, and most people never see the real size of their road footprint. Seeing it in kilograms lets you compare cars, test how a cheaper, lighter or electric vehicle changes the total, and judge reductions such as car-pooling or smaller weekly distances. Nothing you type leaves your browser – the tool is written in HTML, CSS and JavaScript, runs entirely on your device, and sends no data to any server.

This calculator turns your driving details into a complete CO2 report. You supply the distance, the period it applies to, the fuel or energy type, and the consumption rate, and it returns: • daily, weekly, monthly and yearly CO2 emissions; • the total fuel (litres) or electricity (kWh) used in a year; • an optional yearly fuel cost when you enter a local price; • per-person emissions when there is more than one traveller; • the number of trees required to offset a year of driving.

The built-in "Load an example" link fills the form with a typical commuter car so you can see how the tool behaves in one click, and the Copy and Download buttons let you save the result as a formatted text file.

1. Distance and how often you travel it. Enter any distance and choose whether it is your daily, weekly, monthly or yearly total. The tool normalises that figure to a single daily value. For example, 350 km entered as a weekly figure is treated as 50 km per day, which matches a 50 km entry set to daily. Distances can be typed in kilometres or miles and are converted automatically.

2. Fuel type. Choose petrol, diesel, LPG, electric or hybrid. The choice sets the unit and the default emission factor: petrol and hybrid use litres per 100 km, while electric uses kilowatt-hours per 100 km. Picking diesel instead of petrol for the same 4 litres burned each day changes your daily CO2 from 9.24 kg to 10.72 kg, because diesel releases more CO2 per litre.

3. Consumption rate. Type your vehicle's real efficiency from the dashboard, such as 8 L/100km or 15 kWh/100km. The lower the figure, the lower the output – dropping a petrol car from 8 to 6 L/100km cuts daily CO2 from 9.24 kg to 6.93 kg at the same distance. Using a real figure instead of the manufacturer's advertised value gives a much more accurate footprint.

4. Editable emission factor. The factor for your chosen fuel is filled in for you, but you can change it to reflect your regional fuel blend or the emissions of your local electricity grid. This matters most for electric cars, where the grid's energy mix makes the difference between roughly 0.1 and 0.6 kg of CO2 per kWh.

5. Passengers. Set the number of travellers to divide the total and see your share of the footprint. Two people sharing one 9.24 kg-per-day car means each person is responsible for about 4.62 kg a day, which is exactly why car-pooling is such an effective reduction.

6. Fuel price and cost. Optionally enter what you pay per litre or per kWh and the tool adds an estimated yearly fuel bill. A 4-litre-per-day petrol car at a local price of 1.6 per unit uses 4 litres daily – roughly 1,460 litres (about 2,336 in cost) a year – making the link between efficiency, emissions and running cost easy to see.

7. Trees to offset. Your yearly CO2 is divided by the average absorption of a mature tree (21.77 kg per year) to show how many trees would balance a year of driving. A 3,372 kg annual footprint needs about 155 trees – a vivid way to picture the size of the number in kilograms.

8. Live mode. The calculator recalculates automatically as you change any value, so you can compare numbers while you adjust them. Turn Live mode off if you prefer to review your inputs first and only calculate when you press the Calculate button.

1. Comparing vehicles before buying. Enter the advertised consumption of a petrol, hybrid and electric option at your own weekly distance to see which will really produce the least CO2 in your hands.

2. Measuring a lifestyle change. Work out your commute, then test what happens if you car-pool, take public transport two days a week, or switch to a smaller engine. That turns a vague intention to drive less into numbers you can actually act on.

3. Reporting and budgeting. Freelancers or small businesses that log mileage can use the yearly fuel total for planning, and add a local fuel price to estimate annual transport costs alongside the emissions.

4. Learning about emission factors. Because every part of the calculation is visible line by line, it is a handy teaching aid for understanding why fuel efficiency, occupancy and grid emissions all change a vehicle's footprint.

FAQ 1: Is this tool free to use?
Answer: Yes, the Carbon Footprint Calculator is completely free. Everything runs in your browser and no sign-up or login is needed, and no data is sent to any server.

FAQ 2: How accurate is the result?
Answer: It is as accurate as the figures you enter. The emission factors for petrol, diesel and LPG are widely accepted averages, but the electric figure depends heavily on your local grid and the tree figure uses an average absorption rate. Use the editable factor field to refine any of these for your region, and treat the result as a well-calculated estimate rather than a laboratory measurement.

FAQ 3: Are electric vehicles really zero-emission?
Answer: No. Electric cars have no exhaust (tailpipe) emissions, but generating the electricity they use still releases CO2 unless it comes from renewables. The tool applies a grid-based factor to your kilowatt-hours, and you can lower that factor if you mainly charge from solar at home.

FAQ 4: Why does a hybrid use the petrol emission factor?
Answer: Because burning one litre of petrol releases the same amount of CO2 whether it happens in a conventional car or a hybrid. The hybrid's advantage is that it uses noticeably fewer litres per 100 km, and that lower consumption is what the calculator captures.

FAQ 5: What does the "trees to offset" number actually mean?
Answer: It is the number of mature trees, each absorbing about 21.77 kg of CO2 per year, that would balance out a year of your driving. Real trees absorb different amounts depending on species, age and climate, so treat it as an illustrative picture rather than a precise offset guarantee.

FAQ 6: Is the manufacturing of the vehicle included?
Answer: No. This calculator covers operational (driving) emissions only. Building a car produces its own emissions, but these vary hugely by model and are normally calculated separately in a lifecycle analysis.