For UK grid electricity, the converter multiplies your kilowatt-hours by the 2026 government factor for electricity generated, 0.13096 kg CO2e per kWh, and returns a location-based Scope 2 figure in kilograms and tonnes of CO2e. For natural gas burned on site it returns a Scope 1 figure, using 0.18231 kg CO2e per kWh for kilowatt-hours on a UK bill. Optional electricity lines for transmission and distribution losses and well-to-tank supply are shown separately and never added in. Two reporting years are supported: calendar 2026, or a 12-month year with most of its days in 2026, such as April 2026 to March 2027. Any other year or period returns no figures.

Open the converter. Copy the billed kilowatt-hours before typing them here. Keep a meter reading apart from billed kilowatt-hours. Return to the footprint method after this one source.

What the converter returns

The converter is near the end of this page, after the sources. Open the converter if you want the form first. It runs in your browser. It does not send your figures anywhere and it is not a download.

Every result is in CO2e, which counts carbon dioxide, methane and nitrous oxide together. It is not a CO2-only figure. Each line shows its own factor, sheet and cell from the government workbook. There is no combined total, because the lines belong to different scopes and some are optional.

This is not a market-based figure, a live grid reading or a whole-business footprint. Getting the arithmetic right does not show that a bill covers every meter, or that a tariff is renewable.

Reporting year and factor dataset

Choose the reporting year before anything else. The list has no default.

  • Calendar year 2026 means activity from 1 January to 31 December 2026.
  • Most days in 2026 means a 12-month reporting year in which most days fall in 2026, such as 1 April 2026 to 31 March 2027. The government factor guidance calls this the majority approach.
  • Another year or period covers 2025, 2027, a July to June year, a blended-days approach or a period you have not settled. The converter shows no figures for these, so other years never receive 2026 factors by accident.

The government guidance says July to June reporters should apply the newest set available, and that a blended approach splits days between two factor years. Neither case is calculated here. A 2025 baseline should not be reconverted with 2026 factors unless you have a stated restatement method.

The factors come from the Department for Energy Security and Net Zero (DESNZ) conversion factors 2026, full set, Version 1, published on 11 June 2026. The workbook gives June 2027 as the next publication date, and the homeworking sheet labels the same month as expiry. That is when DESNZ plans a new set. It does not change which factors apply to the two supported reporting years, and results here stay tied to the 2026 set. When a 2027 set is published it will be added beside the 2026 factors, not written over them.

The 2026 electricity factor uses 2025 grid data, and the 2025 publication used 2023 data. The methodology paper notes that this skips 2024 and that users who do not restate earlier years should explain the change.

Electricity inputs and separate lines

Enter the kilowatt-hours from a bill or meter. The “where the kWh came from” choice is a label for your records and does not change the factor.

The Scope 2 line is kWh × 0.13096, from the UK electricity sheet, Electricity generated, Electricity: UK, cell E25. The three optional lines are Scope 3:

Line Factor (kg CO2e per kWh) Workbook source
Transmission and distribution losses 0.01299 Transmission and distribution, T&D- UK electricity, cell E22
Well-to-tank, generation 0.03682 WTT- UK electricity, generation, cell E19
Well-to-tank, transmission and distribution 0.00359 WTT- UK electricity, T&D, cell E24

Tonnes are the unrounded kilograms divided by 1,000. Both are shown to five decimal places, rounded half away from zero.

This mode is for electricity bought from the UK grid. Electricity you generate and use on site, overseas grids and contractual instruments such as certificates are outside it.

Zero, missing, invalid, unsupported and stale results

If more than one problem is present, the converter reports the first in this order:

  1. Invalid input: a negative number, text the browser cannot read as a number, a quantity above 1,000,000,000, or a value the form does not offer.
  2. Unsupported year: you chose another year or period.
  3. Gas unit not converted: you chose cubic feet, a calorific value or another gas unit.
  4. Missing input: the reporting year or the quantity is blank.

None of these states shows kilograms. A typed 0 is a valid result of 0.00000 kg and 0.00000 t.

If you change any field after a result, the figures are cleared and you are asked to calculate again. An old result never sits beside new inputs.

Without JavaScript, or if the page script fails, a visible message says the converter is unavailable and the Calculate button stays inactive. Nothing is placed in the address bar. The fields have visible labels, each fuel has its own group, and the result is announced in the page. Everything works with a keyboard.

Natural gas mode on the converter

Choose Natural gas burned on site to switch modes. The result is Scope 1 CO2e from burning mains gas at a site inside your organisation’s boundary, from the Fuels sheet row Natural gas. It is not purchased heat or steam, not a gas leak, and not the emissions from extracting and transporting the gas. No well-to-tank gas line is offered.

The electricity fields are hidden and ignored in gas mode. The reporting-year rules are the same, and no electricity-plus-gas total is shown.

Choose the gas quantity you have

Choice Factor When to use it
kWh on a UK bill (Gross CV) 0.18231 kg CO2e per kWh, Fuels cell D42 The default. UK suppliers calculate billed kilowatt-hours on a gross calorific value basis unless they say otherwise.
kWh stated as Net CV 0.20199 kg CO2e per kWh, Fuels cell D41 Only when the supplier states that the figures are on a net calorific value basis.
Cubic metres, published dataset average 2.02633 kg CO2e per cubic metre, Fuels cell D40 Only when you have chosen to estimate from volume. It is a dataset average.
Cubic feet, a bill calorific value or another unit None No figures are shown. Use the kilowatt-hours your supplier calculated.

Use the kilowatt-hours on the bill whenever you have them. A supplier turns a meter reading into kilowatt-hours using the calorific value printed on the bill and a fixed volume correction set in regulations. The published cubic-metre row does not use your bill’s calorific value or that correction, so a cubic-metre result is an estimate and does not check a bill. The converter has no box for entering your own calorific value.

Worked examples to check

These are fictional Northgate Services quantities for calendar year 2026, not real bills.

Inputs Result
1,000 kWh electricity, no optional lines Scope 2: 130.96000 kg, 0.13096 t
200,000 kWh electricity Scope 2: 26,192.00000 kg, 26.19200 t
1,000 kWh with all three optional lines Scope 2: 130.96000 kg. Transmission and distribution: 12.99000 kg. Well-to-tank generation: 36.82000 kg. Well-to-tank transmission and distribution: 3.59000 kg. Shown separately with no total.
0 kWh 0.00000 kg, 0.00000 t
Blank kWh Missing input, no kilograms
−1 kWh Invalid input, no kilograms
1,000 kWh with "another year or period" Unsupported year, no kilograms

Gas examples to check

Inputs Result
1,000 kWh, Gross CV 182.31000 kg, 0.18231 t
60,000 kWh, Gross CV 10,938.60000 kg, 10.93860 t
1,000 kWh, Net CV 201.99000 kg, 0.20199 t
10 cubic metres, published average 20.26330 kg, 0.02026 t, with the estimate note
500 in another unit Gas unit not converted, no kilograms
0 kWh, Gross CV 0.00000 kg

Gas limits

A matching result does not show that the bill covers every meter or month. Biomethane certificates, heat networks and gas used in vehicles are outside this mode. Gas totals for a whole year still belong in your period records: keep the gas readings and billed kilowatt-hours in one period log.

Limits and sources

A location-based line is not a market-based figure, and a green-tariff sentence does not change it. Read when a contract can set a market-based figure, and keep the location-based figure when a tariff is called green. One energy line is not an organisational inventory. Check coverage with the footprint method.

Sources:

Convert kWh or gas to CO2e

Choose the reporting year first, then the fuel. Inputs stay in this page and are not sent anywhere. Each result line is shown separately and lines are never added together.

The converter is unavailable because the page script did not start. The form is left inactive so your figures stay on this page.

Reporting year and fuel

Only 2026 factors are loaded. Another year, a July to June year or a blended-days approach returns no figures.

Electricity

A label for your records. It does not change the factor.

Optional Scope 3 lines, each shown separately:

Choose a reporting year and enter a quantity to see kilograms and tonnes of CO2e. The Calculate button stays inactive until the page script starts.

Factors: DESNZ greenhouse gas conversion factors 2026, full set, Version 1, published 11 June 2026. DESNZ plans the next set for June 2027; results here stay tied to the 2026 set.