Carbon Footprint Calculator
A household's yearly carbon footprint from electricity, natural gas, heating oil, LPG and car fuel, with a breakdown by source and per person, using published government emission factors.
Result…
How it's calculated
Emissions (kg CO2e) = amount × factor, for each source Electricity: kWh × grid factor; gas: kWh, m³ or therms × DESNZ factor (1 therm = 29.30711 kWh) Liquid fuels: litres × DESNZ factor (1 US gallon = 3.785411784 litres) Per person = total ÷ people in the home
Adds up a household's yearly emissions from electricity, natural gas, heating oil, LPG and car petrol or diesel. Fuel factors come from the UK Department for Energy Security and Net Zero's Greenhouse gas reporting conversion factors 2026; for electricity choose the DESNZ 2026 UK factor, the US EPA eGRID2023 national average (770.884 lb CO2e per MWh) or your own supplier's or country's factor. Gas can be in kWh, cubic metres or therms and liquid fuels in litres or US gallons, with exact conversions. It shows each source's share and the footprint per person.
Your numbers, step by step
About the Carbon Footprint calculator
This carbon footprint calculator adds up a household's yearly greenhouse gas emissions from home energy and car fuel, in kilograms of carbon dioxide equivalent (CO2e). Enter a year of electricity, natural gas, heating oil, LPG, petrol and diesel use from your bills and fuel receipts. Electricity is multiplied by a grid factor you choose: the UK government's 2026 figure from the Department for Energy Security and Net Zero (DESNZ), the US EPA's eGRID2023 national average, or your own supplier's or country's factor. Fuels use the DESNZ 2026 conversion factors, with gas in kWh, cubic metres or therms and liquid fuels in litres or US gallons. You get the total, the amount per person and a chart of each source's share, so you can see where a change would count most. Every multiplication is shown.
How to use it
- Pick the “Electricity grid factor”, or choose “Enter my own factor” and type it in kg CO2e per kWh.
- Enter “Electricity used per year” in kWh and “Natural gas per year” in the “Natural gas unit” on your bill.
- Choose litres or US gallons under “Liquid fuels in”, then enter any heating oil, LPG, petrol and diesel used in a year.
- Enter the “People in the home” for the footprint per person.
- Read the yearly total, the per-person figure and the breakdown by source.
Worked example
A two-person UK home uses 2,700 kWh of electricity, 11,500 kWh of gas and 600 litres of petrol a year. Electricity: 2,700 × 0.13096 = 353.6 kg. Gas: 11,500 × 0.18231 = 2,096.6 kg. Petrol: 600 × 2.075 = 1,245 kg. The total is 353.6 + 2,096.6 + 1,245 = 3,695.2 kg CO2e a year (3.70 tonnes), or 1,847.6 kg per person.
Updated
Questions people ask
How do I calculate my household carbon footprint?
Multiply each year's energy or fuel use by its emission factor and add the results. For example, kWh of electricity × the grid factor, plus litres of petrol × 2.075 kg CO2e per litre from the UK government's conversion factors 2026.
What grid factor should I use for my electricity?
Use the factor for your own country or region, or your supplier's if it publishes one, because grids range from almost all renewable or nuclear power to mostly coal. The UK 2026 factor is 0.13096 kg per kWh and the US eGRID2023 average is 770.884 lb per MWh, about 0.35 kg per kWh.
How do I convert gas therms or cubic metres to emissions?
Choose the unit on your bill. The calculator uses DESNZ's factors of 0.18231 kg CO2e per kWh and 2.02633 kg per cubic metre, and 1 therm = 29.30711 kWh from the DESNZ conversions table.
Is a green electricity tariff counted as zero?
Only if you enter your own factor. This calculator uses the average grid factor you pick, so check how your supplier backs its tariff before entering 0.
What does this carbon footprint leave out?
It covers home energy and car fuel only, not flights, food, goods or services, and it counts electricity at the power station, without grid losses or the emissions of producing fuels. Add trips with the flight carbon calculator and compare running costs with the electricity cost calculator.