Carbon accounting services for UK businesses

What is carbon accounting?

Carbon accounting is the process of measuring, recording and reporting the greenhouse gas emissions your organisation produces over a reporting period, expressed in tonnes of carbon dioxide equivalent (CO2e). The "equivalent" matters: carbon accounting converts every greenhouse gas — carbon dioxide, methane, nitrous oxide, refrigerants — into a single CO2e figure using each gas's global warming potential. That gives you one emissions number you can track, compare and reduce.

Done properly, carbon accounting — sometimes called carbon accountancy or GHG accounting — follows the GHG Protocol and produces a corporate carbon footprint that splits emissions into three scopes. It answers two questions every board now asks: where are our carbon emissions coming from, and how big is our environmental impact? Good carbon accounting and reporting is the first step on any credible net zero journey and wider carbon management programme, and it underpins everything from a SECR filing to a customer tender.

Carbon accounting services, without the guesswork

Most UK businesses do not need to hire an in-house carbon accountant or buy a carbon accounting platform they will use once a year. They need a credible emissions number, produced to a recognised standard, in a format their stakeholders will accept. That is what our matched carbon accounting services deliver.

We are an introduction service, not a consultancy that files on your behalf. We do not employ named consultants and we do not do the carbon accounting ourselves. Instead, we connect you with one vetted, IEMA-qualified specialist who scopes the work, measures your emissions and hands you an audit-ready report. You deal with a single accountable expert, not a sales funnel.

Who carbon accounting services are for

These carbon accounting services suit UK businesses of any size — from SMEs taking a first measurement to large organisations and listed companies that need an audit-ready inventory. You are a good fit if you need:

• A SECR submission and the scope 1 + 2 emissions data behind it.
• A carbon footprint for a customer tender or a PPN 06/21 Carbon Reduction Plan.
• B Corp certification or recertification, an EcoVadis rating, or a CDP disclosure.
• An investor or lender questionnaire answered with credible carbon data.
• A baseline before you set targets and build a net zero strategy.

If you are unsure whether you are even in scope for mandatory reporting, start with our SECR eligibility checker.

What's included in the service

A specialist delivers a complete carbon accounting and reporting package, not a spreadsheet you have to interpret:

• A defined organisational boundary and reporting period, set using operational control.
• A full greenhouse gas inventory across scope 1, scope 2 and material scope 3 emissions.
• Calculations using the current DEFRA (DESNZ) 2025 conversion factors, the UK's official emission factors.
• A written report aligned to the GHG Protocol and ISO 14064-1:2018, with an intensity ratio.
• A data-quality rating for each scope 3 category, so you know which carbon data is robust.
• Clear next steps: where to cut carbon emissions first and how to set targets.

What carbon accounting measures: scope 1, 2 and 3 emissions

The GHG Protocol splits a corporate carbon footprint into three scopes of emissions:

• Scope 1 emissions — direct emissions from owned or controlled sources: natural gas, your owned fleet, process emissions and refrigerant leakage. See our scope 1 emissions guide.
• Scope 2 emissions — indirect emissions from purchased electricity, heat and steam, reported location-based and, where relevant, market-based. See our scope 2 emissions guide.
• Scope 3 emissions — all other indirect emissions across your value chain and supply chain, screened across the 15 GHG Protocol categories: purchased goods and services, business travel, employee commuting, waste and more. See our scope 3 emissions guide and scope 3 emissions consultancy.

Scopes 1 and 2 together form the minimum corporate carbon footprint. Scope 3 is usually the largest part of total carbon emissions but the hardest to measure, which is exactly where an experienced carbon accountant earns their fee.

How carbon accounting works: the method

Carbon accounting is simple in principle and fiddly in practice. The formula is the same for every source:

Activity data × emission factor = emissions in CO2e.

Activity data is the thing you did — litres of diesel, kilowatt-hours of electricity, miles driven, tonnes of waste. The emission factor converts that activity into CO2e. The skill is not the multiplication; it is choosing the right boundary and the right emission factor for each activity so the number survives an auditor's questions.

Step	What the specialist does
1. Set the boundary	Decide what to include using operational control, and fix the reporting period
2. Gather activity data	Fuel, gas and electricity, fleet, travel, waste, purchased goods and services
3. Apply emission factors	Multiply each activity by the current DEFRA conversion factor to get CO2e
4. Report and reduce	Total the emissions, set an intensity ratio, and plan ways to reduce them

What data you need to start

You do not need everything on day one. To measure your emissions a specialist mainly needs your annual gas and electricity use in kWh, fleet fuel or mileage, business travel and employee commuting, waste by disposal route, and spend or quantities for your largest scope 3 categories. They send a short, structured data request so you only gather what the calculation needs.

Want a rough number before you commit? Our free SECR carbon calculator turns activity data into a CO2e estimate using the current DEFRA factors, and the DEFRA conversion factors tool lets you look up individual emission factors. Use the calculator to size the work; the specialist then produces the audit-ready version.

Why a specialist beats DIY or a generalist accountant

A spreadsheet can multiply numbers. It cannot tell you whether your boundary is right, whether you have double-counted, or whether your scope 3 screening is defensible. Carbon accounting software platforms help large teams manage data, but the licence does not make the methodology decisions for you — and a general-practice accountant rarely has the GHG Protocol experience the work demands.

An IEMA-qualified specialist gets the boundary, the scopes and the emission factors right first time, so your emissions data holds up to a SECR auditor, a CDP reviewer or a tender authority. That is the difference between a number you can publish and a number you have to defend.

What carbon accounting standards to follow

The work follows the GHG Protocol Corporate Accounting and Reporting Standard, aligned to ISO 14064-1:2018, using the current-year DEFRA conversion factors. This is the standard recognised by SECR auditors, CDP, B Corp, EcoVadis, SBTi and UK public-sector tender authorities. Aligning to international standards means your carbon footprint travels: the same emissions number works for a tender, a CDP submission and an investor questionnaire. Footprints prepared to ISO 14064-1 can also be third-party verified by an independent assurer.

Is carbon accounting mandatory in the UK?

For many large organisations, yes. SECR is mandatory for large UK companies that meet two of three thresholds: turnover of £36m or more, a balance sheet of £18m or more, or 250 or more employees. The April 2025 Companies Act uplift raised the general "large" company thresholds, but the SECR thresholds did not move — so a company now classed as medium can still be in scope for SECR. ESOS is a separate regime with its own thresholds (250 or more staff, or turnover above £44m and a balance sheet above £38m). Even where reporting is voluntary, tenders and lenders increasingly require a carbon footprint and a Carbon Reduction Plan.

Built to work for SECR

A carbon footprint built scope 1 + 2 first, with the UK split and an intensity ratio, drops straight into a SECR filing. If you also need SECR filed, you can bundle it — see our SECR reporting services. The same DEFRA emission factor methodology underpins both, so you measure once and report everywhere.

From baseline to net zero

A carbon footprint is a baseline, not an end point. Once you know your emissions you can set a science-aligned reduction target, tackle the biggest sources first, switch to a renewable electricity tariff to cut location-based scope 2, and publish a Carbon Reduction Plan so you can bid for contracts that require one. Build the wider plan with our net zero strategy service. Most organisations repeat their carbon accounting annually, matched to their financial year, so they can benchmark a trend toward net zero by 2050, support a credible carbon neutrality or climate action claim, and prove progress to customers and investors.

Pricing and how matching works

These carbon accounting services are free to use — you pay only the specialist, on a fixed fee, for the work itself. There is no retainer and no obligation. For an indication of what a footprint costs, see our pricing. Tell us about your company and we connect you with a single vetted, IEMA-qualified specialist who gets in touch within one working day to scope the work and give you a fixed-fee, no-obligation quote. Get matched today.