This calculator
Electricity, gas, diesel, petrol and car miles; grid losses if you tick them.
A quick, sourced estimate of Scopes 1 and 2.Tool · business carbon footprint, 2026 factors
Carbon footprint calculator for business
Enter a year of your business’s electricity, gas, fuel and mileage, and see its carbon footprint by scope on the UK government’s 2026 conversion factors.
Every factor and its source is shown; nothing you enter is stored or sent.
The calculator
What is your business’s carbon footprint?
Replace the example figures with yours, from bills, fuel cards and mileage claims for activity in 2026.
Your business footprint · DESNZ 2026 factors
Estimated total: 44.64 tCO2e a year
Scope 124.92 tCO2e
Scope 215.72 tCO2e
Scope 34.00 tCO2e
| Line | Factor (kgCO2e) | Scope | tCO2e |
|---|---|---|---|
| Grid electricity used | 0.13096 / kWh | Scope 2 | 15.72 |
| Natural gas used (as billed) | 0.18231 / kWh | Scope 1 | 14.58 |
| Diesel bought for company vehicles or plant | 2.58354 / litre | Scope 1 | 10.33 |
| Petrol bought for company vehicles | 2.07500 / litre | Scope 1 | 0.00 |
| Business miles in cars (fuel not bought by the company) | 0.26699 / mile | Scope 3 | 4.00 |
Factors: DESNZ conversion factors 2026 (flat file, revised July 2026) · electricity from the 2026 methodology paper, Table 9.
For activity in 2026 only. Location-based Scope 2; gas assumes your bill is on a gross calorific value basis, as UK supplier kWh generally are. An estimate, not a SECR figure or a verified inventory. Nothing is stored or sent.
Reading the result
What do Scope 1, 2 and 3 mean in your result?
Scope 1 is the fuel your business burns in boilers and vehicles it owns or controls, Scope 2 is the electricity it buys, and Scope 3 is everything else in its value chain, under the GHG Protocol Corporate Standard.
The electricity line is location-based, using the national grid factor, which is the method UK SRS S2 requires, according to the standard.
A market-based figure, using your supplier’s contracts and certificates, is a second calculation the Scope 2 Guidance describes and this calculator does not make.
Three scopesKey facts
Three scopes
Scope 1
Your fuel
Gas, diesel and petrol you burn, in buildings and vehicles you control
The factors
Which factors does the calculator use, and from where?
| Activity | 2026 factor, kgCO2e | Scope | Source |
|---|---|---|---|
| UK grid electricity, generated | 0.13096 per kWh | 2 | DESNZ methodology, Table 9 |
| Transmission and distribution losses | 0.01299 per kWh | 3 | DESNZ methodology, Table 9 |
| Natural gas, Gross CV | 0.18231 per kWh | 1 | DESNZ flat file, July 2026 |
| Diesel, average biofuel blend | 2.58354 per litre | 1 | DESNZ flat file, July 2026 |
| Petrol, average biofuel blend | 2.07500 per litre | 1 | DESNZ flat file, July 2026 |
| Average car, fuel unknown | 0.26699 per mile | 1 if owned or leased; 3 if an employee’s car | DESNZ flat file, July 2026 |
DESNZ says gas consumption quoted in kWh by UK suppliers is generally on a gross calorific value basis, so the gross factor is the default unless your supplier says otherwise, at ¶2.9 of its methodology paper.
“Average biofuel blend” is the fuel sold at UK forecourts; the 100% mineral fuels have separate, higher factors.
The factor year
Can you use 2026 factors for any year’s data?
- 1 January 202601
Activity year begins
The factors on this page are for activity falling entirely or mostly within 2026. - 11 June 202602
- 31 July 202603
Flat file corrected
Some values shown as 0 were restored to blank; the full set was not revised. - June 202704
Use the set for the year in which the energy was used, not the year in which you report it.
The UK electricity factor fell by about 26% from the 2025 to the 2026 set, mostly grid decarbonisation and 6 to 7 percentage points from a change of method, according to DESNZ’s major changes report, so the same use gives a lower figure this year.
Picking the right year’s factorsExplore
Picking the right year’s factors
Activity year
Use the set for the year the energy was used.
Picking the right year’s factors
Full set or flat file
The condensed set is no longer published from 2026.
Picking the right year’s factors
Blanks
A blank factor is missing data, not zero.
Picking the right year’s factors
Last year
Keep last year’s figure on last year’s factors.
What it leaves out
What does a five-line calculator not count?
It leaves out most of Scope 3: purchased goods and services, waste, rail and air travel, commuting and the other value-chain categories of the Scope 3 Standard.
It also leaves out refrigerant leaks, which are Scope 1, and the well-to-tank emissions of the fuels you burn.
For many businesses Scope 3 is the larger part, so treat the result as the part of the footprint you control most directly, not the whole of it.
The software that measures the rest is covered on carbon footprint software and Scope 3 emissions software.
Your
footprint
footprint
A full inventory
All Scope 1 sources including refrigerants, both Scope 2 methods, and the Scope 3 categories that apply.
What carbon accounting software and an auditor work to.Reporting
Does your business have to report this?
SECR size test
Two of three£36m turnover, £18m balance sheet, 250 employeesLow-energy relief
40,000 kWhOr less, on all forms of energyMean annual cost of SECR
£7,100Per complier, DESNZ evaluationStaff time
about 94 hoursA year, DESNZ evaluationMost small businesses do not have to report their footprint: 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.
A company in SECR that used 40,000 kWh or less may state that instead of disclosing its figures, and the threshold counts every form of energy.
SECR also needs energy in kWh, at least one intensity ratio, the methodology, efficiency measures and last year’s figures, which a calculator does not produce; see SECR reporting software.
Read where else a footprint is asked for
Suppliers bidding for major government contracts may be asked for a Carbon Reduction Plan under PPN 006; the detail is on Carbon Reduction Plans.
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.
When the footprint becomes a dutyExplore
When the footprint becomes a duty
SECR, unquoted company
Only if it exceeds two of £36m turnover, £18m balance sheet and 250 employees.
When the footprint becomes a duty
Low energy use
40,000 kWh or less: the figures may be replaced by a statement saying so.
When the footprint becomes a duty
Public contracts
A Carbon Reduction Plan may be asked for in major government procurements.
When the footprint becomes a duty
Listed companies
UK SRS S2 on a comply-or-explain basis for periods from 1 January 2027.
From calculator to software
When is a calculator no longer enough?
A calculator is enough while the business has a handful of meters, one fleet and nobody auditing the figure.
It stops being enough when there are many sites, a group structure, Scope 3 to measure, last year’s figures to keep fixed, or a report someone will sign.
DESNZ’s evaluation put the mean ongoing cost of SECR at about £7,100 a year and about 94 hours of staff time per complier, which is the cost software is bought to reduce.
The worksheet beside this compares a platform quote with the hours your current process takes, and the buying guide is carbon accounting software for small business.
An estimate, not a verified figure
The calculator is arithmetic on published factors; it is not an audited inventory or a SECR report.
Platform against the way you work now
Current process £0 a year · quote £0 a year
Fill in all three to see the break-even hours.
Arithmetic on your own inputs.
The quote’s implementation, uplift and exit terms are in the three-year worksheet on the carbon reporting software page.
Nothing is stored or sent.
For the board
Your footprint, in one sentence
Five figures from our bills give us the part of our footprint we control most, and the rest is in what we buy.
Takeaways
Five facts, then the next step
| Fact | Source |
|---|---|
| 2026 factors are for activity mostly within 2026. | DESNZ ¶1.10 |
| UK grid electricity is 0.13096 kgCO2e per kWh in the 2026 set. | DESNZ Table 9 |
| Supplier gas kWh is gross CV by default: 0.18231 kgCO2e per kWh. | DESNZ ¶2.9; flat file |
| Most small businesses are outside SECR. | SI 2008/410 Sch 7 ¶20B |
| Scope 3 is not in this estimate and is often the largest part. | GHG Protocol Scope 3 Standard |
Next: keep this year’s inputs with their bills, and see carbon accounting software when you need Scope 3 or a figure someone will audit.
Frequently asked
Business carbon footprint calculator, answered
How do I calculate my business’s carbon footprint?
Multiply each activity by its conversion factor and add them up: electricity in kWh, gas in kWh, fuel in litres and business miles.
In the UK the factors come from DESNZ, one set a year.
The calculator on this page does that arithmetic on the 2026 set and shows every factor it used.
Which conversion factors does this calculator use?
The DESNZ 2026 factors: UK grid electricity 0.13096 kgCO2e per kWh generated, natural gas 0.18231 per kWh on a gross calorific value basis, diesel 2.58354 per litre and petrol 2.07500 per litre (average biofuel blends), and an average car of unknown fuel at 0.26699 per mile.
Can I use 2026 factors for last year’s activity?
No. DESNZ says the 2026 factors are for activity data falling entirely or mostly within 2026.
For 2025 activity use the 2025 set; the electricity factor alone fell by about a quarter between them, so mixing years distorts the result.
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 by default unless your supplier says it used net.
Are employees’ own cars Scope 1 or Scope 3?
Under the GHG Protocol, cars the company owns or leases are Scope 1 and employees’ own cars used on business are Scope 3.
For an unquoted company’s SECR report, fuel for business journeys counts in the transport line where the company is responsible for buying it, which includes reimbursed mileage.
The calculator lets you choose.
Is this a SECR report?
No. SECR applies to quoted companies, large unquoted companies and large LLPs, and requires energy in kWh, emissions, at least one intensity ratio, the methodology, efficiency measures and last year’s figures in the directors’ report. This calculator gives an estimate of the emissions lines only.
Does my business have to report its carbon footprint?
Most small businesses do not.
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 it, for example through a Carbon Reduction Plan under PPN 006.
What does this calculator leave out?
Most of Scope 3: purchased goods and services, waste, business travel by rail and air, commuting and the other value-chain categories, as well as refrigerant leaks and well-to-tank emissions from fuels.
For many businesses Scope 3 is the largest part of the footprint.
Why is my electricity footprint lower than last year with the same use?
Because the factor moved.
The UK electricity factor fell by about 26% from the 2025 to the 2026 set, mostly from grid decarbonisation and partly from a change of method, according to DESNZ.
What happened to the condensed set of factors?
DESNZ stopped publishing it in 2026.
Its methodology paper says the condensed set is no longer published; the full set and the flat file remain.
What do CO2e figures include?
Carbon dioxide plus methane and nitrous oxide expressed as CO2 equivalents.
The 2026 DESNZ factors use the IPCC’s fifth assessment values: 28 for methane and 265 for nitrous oxide.
When should a business move from a calculator to software?
When there are many sites or meters, a fleet, a group structure, Scope 3 to measure, or a report someone will audit.
Below that, a calculator and a spreadsheet with the published factors is often enough.
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 16 sources fromDepartment for Energy Security and Net ZeroGHG Protocol (WRI, WBCSD)GHG Protocollegislation.gov.ukGOV.UK (DESNZ, Defra)Department for Business and Trade
- Department for Energy Security and Net ZeroGreenhouse gas reporting: conversion factors 2026
Published 11 June 2026; flat file corrected 31 July 2026.
- Department for Energy Security and Net ZeroConversion factors 2026: flat file (revised July 2026)
Natural gas, diesel, petrol and average car 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 CV for 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 (collection)
Every year’s set, for activity in that year.
- GHG Protocol (WRI, WBCSD)Corporate Accounting and Reporting Standard
Scopes 1, 2 and 3 and the five accounting principles.
- GHG ProtocolCorporate Value Chain (Scope 3) Standard
The 15 categories a calculator like this leaves out.
- GHG ProtocolScope 2 Guidance
Location-based and market-based electricity.
- legislation.gov.ukSI 2008/410, Schedule 7 (SECR)
Who reports, what lines, and the 40,000 kWh relief.
- legislation.gov.ukSI 2008/410, Schedule 7 paragraph 20B
The size test for unquoted companies.
- legislation.gov.ukSI 2008/410, Schedule 7 paragraph 20D
An unquoted company’s energy and emissions lines, including transport fuel.
- GOV.UK (DESNZ, Defra)Environmental Reporting Guidelines, including SECR requirements
Government guidance on company reporting.
- Department for Business and TradeUK SRS S2 Climate-related Disclosures (PDF)
Location-based Scope 2; no factors prescribed.
- 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.
- Department for Energy Security and Net ZeroStreamlined Energy and Carbon Reporting regulations: evaluation
What reporting costs a complier in time and money.
- GOV.UKPPN 006: taking account of Carbon Reduction Plans in the procurement of major government contracts
Where a supplier’s footprint is asked for in procurement.