This calculator
Energy, road fuel or miles, flights and rail.
What you can read off bills and bookings.Tool · carbon footprint, 2026 factors
Carbon footprint calculator: home, road and travel, on the 2026 factors
This carbon footprint calculator turns a year of energy, driving, flights and rail into tonnes of CO2e, for a UK household or a small business.
It uses the UK government’s 2026 conversion factors, shows each one, and stores nothing you enter.
The calculator
What is your carbon footprint?
Choose household or small business, then replace the example figures with a year of yours.
Carbon footprint · DESNZ 2026 factors
Enter car miles or fuel litres for the same journeys, not both.
Estimated household footprint: 4.62 tCO2e a year
Home or premises2.45 tCO2e
Road1.87 tCO2e
Travel0.30 tCO2e
| Line | Factor (kgCO2e) | tCO2e |
|---|---|---|
| Grid electricity | 0.13096 / kWh | 0.35 |
| Natural gas (as billed) | 0.18231 / kWh | 2.10 |
| Car miles (if you do not know the fuel used) | 0.26699 / mile | 1.87 |
| Petrol bought | 2.07500 / litre | 0.00 |
| Diesel bought | 2.58354 / litre | 0.00 |
| Domestic flights (one-way km × trips) | 0.22928 / passenger km | 0.00 |
| Short-haul flights to or from the UK | 0.12786 / passenger km | 0.28 |
| Long-haul flights to or from the UK | 0.15282 / passenger km | 0.00 |
| National rail | 0.03092 / passenger km | 0.02 |
Factors: DESNZ conversion factors 2026 (flat file, revised July 2026) · electricity from the 2026 methodology paper, Table 9. Flights include radiative forcing.
For 2026 activity. DESNZ publishes these factors for company reporting; used for a household they give an estimate, not a measured figure. Nothing is stored or sent.
Reading the result
Which part of your result is largest, and why?
The result is grouped by where it comes from, because that is where a household or a small firm can act.
Flights are often the largest single line, since a long-haul passenger kilometre carries 0.15282 kgCO2e with radiative forcing, about five times national rail’s 0.03092, in the DESNZ 2026 flat file.
Heating comes next for most homes, at 0.18231 kgCO2e per kWh of gas on the gross basis UK suppliers bill on.
A business that needs its answer by Scope 1, 2 and 3 should use the carbon footprint calculator for business.
Three groups in the resultExplore
Three groups in the result
Home or premises
Electricity and gas: the figures on your bills.
Three groups in the result
Not counted
Food, goods and services; most business Scope 3.
The factors
Where does every number in the calculator come from?
| Activity | 2026 factor, kgCO2e | DESNZ row |
|---|---|---|
| UK grid electricity, generated | 0.13096 per kWh | Methodology paper, Table 9 |
| Natural gas, gross calorific value | 0.18231 per kWh | Fuels › Gaseous fuels |
| Petrol, average biofuel blend | 2.07500 per litre | Fuels › Liquid fuels |
| Diesel, average biofuel blend | 2.58354 per litre | Fuels › Liquid fuels |
| Average car, fuel unknown | 0.26699 per mile | Passenger vehicles › Cars (by size) |
| Domestic flight, average passenger, with RF | 0.22928 per passenger km | Business travel – air |
| Short-haul flight to or from the UK, with RF | 0.12786 per passenger km | Business travel – air |
| Long-haul flight to or from the UK, with RF | 0.15282 per passenger km | Business travel – air |
| National rail | 0.03092 per passenger km | Business travel – land |
DESNZ expresses methane and nitrous oxide as CO2 equivalents using the IPCC’s fifth assessment values, 28 and 265, at ¶1.9 of its methodology paper.
Flight factors are published with and without radiative forcing; for a long-haul average passenger the two are 0.15282 and 0.09043, so a figure should always say which it used.
The factor year
Which year’s factors should you use?
- 1 January 202601
Activity year begins
The 2026 factors are for activity falling entirely or mostly within 2026. - 11 June 202602
- 31 July 202603
- June 202704
Use the set for the year the energy was used or the journey made, not the year you calculate.
The electricity factor fell by about 26% from 2025 to 2026, so the same use gives a lower figure this year, as the major changes report explains.
Getting the year rightExplore
Getting the year right
Full set or flat file
The condensed set is no longer published from 2026.
Getting the year right
Compare like with like
Last year’s figure stays on last year’s factors.
What it leaves out
What can a carbon footprint calculator not tell you?
It counts what you can read off bills, fuel receipts and bookings, and leaves out what you buy.
For a business those purchases are Scope 3, which the Scope 3 Standard divides into 15 categories and which is often the largest part of a footprint.
DESNZ publishes its factors for company reporting and says other uses are at the user’s own risk, in its collection notes, so a household figure is an estimate.
An estimate, not a verified figure
Arithmetic on published factors; not an audited inventory, a SECR report or the basis for a public claim.
Your
footprint
footprint
A full footprint
Plus food, goods and services for a household; all relevant Scope 3 categories for a business.
Often the larger part.Reporting
When does a business footprint become a legal duty?
A household has no duty to calculate anything, and most small businesses have none either.
An unquoted company is in SECR only if it exceeds two of £36m turnover, £18m balance sheet and 250 employees, under paragraph 20B of Schedule 7 to SI 2008/410.
Listed companies in UKLR 6, 14, 15, 16 and 22 report against UK SRS on a comply-or-explain basis for periods beginning on or after 1 January 2027, under PS26/19.
Read what changes once a footprint is reported
SECR needs energy in kWh, at least one intensity ratio, a methodology statement and last year’s figures, which no calculator produces; see SECR reporting software.
A footprint used in an advert or on a label is an environmental claim, and the CMA’s Green Claims Code applies.
Where a footprint is requiredExplore
Where a footprint is required
SECR, unquoted company
Only above two of £36m turnover, £18m balance sheet, 250 employees.
Where a footprint is required
Public contracts
A Carbon Reduction Plan may be required in major government procurements.
Where a footprint is required
Listed companies
UK SRS S2, comply or explain, periods from 1 January 2027.
Where a footprint is required
Households
No duty; the calculation is for your own use.
In one sentence
The whole page, said once
Our bills and bookings tell us most of what we burn, and the rest is in what we buy.
Takeaways
Five facts, then the next step
| Fact | Source |
|---|---|
| The 2026 factors are for activity mostly within 2026. | DESNZ ¶1.10 |
| UK grid electricity is 0.13096 kgCO2e per kWh in 2026. | DESNZ Table 9 |
| A long-haul passenger km is 0.15282 kgCO2e with radiative forcing. | DESNZ flat file |
| DESNZ factors are for company reporting; other uses are at the user’s risk. | DESNZ collection |
| Most small businesses are outside SECR. | SI 2008/410 Sch 7 ¶20B |
Next: for a business answer by scope, open the business calculator; for one product, the product carbon footprint calculator.
Frequently asked
Carbon footprint calculator, answered
How do I calculate my carbon footprint?
Multiply each activity by its conversion factor and add the results: electricity and gas in kWh, fuel in litres or miles driven, and distance flown or travelled by rail.
The calculator on this page does that arithmetic on the UK government’s 2026 factors and shows every factor it used.
Is this a personal or a business carbon footprint calculator?
Both.
Choose “My household” or “My small business”; the factors are the same, the starting figures and the reading differ.
For a business answer by scope, use the carbon footprint calculator for business.
Whose factors does it use?
The Department for Energy Security and Net Zero’s 2026 conversion factors.
DESNZ publishes them for company reporting and says other uses are at the user’s own risk, so a household result is a good estimate, not a measured figure.
Why do the flight figures include radiative forcing?
Aircraft emissions at altitude have warming effects beyond their CO2.
DESNZ publishes each flight factor with and without radiative forcing; this calculator uses the “with” rows, for example 0.15282 kgCO2e per passenger km for an average long-haul passenger, against 0.09043 without.
How do I enter a flight?
As passenger kilometres: the one-way distance multiplied by the number of journeys.
A return trip of 1,000 km each way is 2,000 passenger km.
Should I enter miles or litres for my car?
One or the other for the same journeys, never both.
Litres are more precise; miles use DESNZ’s average car of unknown fuel, 0.26699 kgCO2e per mile.
Is my gas bill in gross or net kWh?
UK suppliers generally quote gas in kWh on a gross calorific value basis, so DESNZ says to use the gross factor, 0.18231 kgCO2e per kWh, unless your supplier says otherwise.
Why is my electricity footprint lower than last year?
Because the factor moved.
The UK electricity factor fell by about a quarter between the 2025 and 2026 sets, mostly from a cleaner grid and partly from a change of method, according to DESNZ.
Can I use these factors for last year?
No. DESNZ says the 2026 factors are for activity falling entirely or mostly within 2026.
Use the 2025 set for 2025 activity.
What does a calculator like this leave out?
For a household, food, goods and services bought; for a business, most of Scope 3, including purchased goods, waste and commuting.
These are often the largest part, so treat the result as the part you can read off your bills.
Does my small business have to report its footprint?
Usually not by law.
An unquoted company is in SECR only if it exceeds two of £36m turnover, £18m balance sheet and 250 employees.
Customers and public buyers may still ask, for example through a Carbon Reduction Plan under PPN 006.
Is anything I enter stored?
No. The calculation runs in your browser; nothing is stored or sent.
Sources
Primary sources
Every factor on this page traces to the DESNZ publication listed here.
Checked against 17 sources fromDepartment for Energy Security and Net ZeroIPCCGHG Protocol (WRI, WBCSD)GHG Protocollegislation.gov.ukGOV.UK (DESNZ, Defra)
- Department for Energy Security and Net ZeroGreenhouse gas reporting: conversion factors 2026
Published 11 June 2026; the flat file corrected 31 July 2026.
- Department for Energy Security and Net ZeroConversion factors 2026: flat file (revised July 2026)
Gas, fuel, car, flight and rail rows used by the calculator.
- Department for Energy Security and Net Zero2026 conversion factors methodology paper, ¶¶1.9, 1.10, 2.3, 2.9 and Table 9
GWPs, the activity-year rule, the end of the condensed set, gross gas, and electricity.
- Department for Energy Security and Net Zero2026 conversion factors: major changes report
Why the electricity factor fell by about a quarter.
- Department for Energy Security and Net ZeroGovernment conversion factors for company reporting
Published for company reporting; other uses at the user’s own risk.
- Department for Energy Security and Net ZeroUK greenhouse gas emissions statistics
The national inventory these factors are consistent with.
- IPCCAR6 Working Group I report
The physical science behind CO2-equivalence.
- GHG Protocol (WRI, WBCSD)Corporate Accounting and Reporting Standard
Scopes 1, 2 and 3 for an organisation.
- GHG ProtocolCorporate Value Chain (Scope 3) Standard
Business travel and the other value-chain categories.
- GHG ProtocolScope 2 Guidance
Location-based and market-based electricity.
- legislation.gov.ukSI 2008/410, Schedule 7 (SECR)
Which companies must report energy and carbon.
- legislation.gov.ukSI 2008/410, Schedule 7 paragraph 20B
The size test for unquoted companies.
- GOV.UK (DESNZ, Defra)Environmental Reporting Guidelines, including SECR requirements
Government guidance on company reporting.
- GOV.UKPPN 006: Carbon Reduction Plans in procurement
Where a supplier’s footprint is asked for.
- Department for Business and TradeUK SRS S2 Climate-related Disclosures (PDF)
Location-based Scope 2 for listed reporting.
- Financial Conduct AuthorityPS26/19 — final rules on UK SRS reporting by listed companies
Comply or explain for periods beginning on or after 1 January 2027.
- Competition and Markets AuthorityGreen Claims Code
If a footprint is used in a public claim.