Carbon audit · UK
Carbon audit services for UK businesses
A carbon audit is an independent review of a carbon footprint you have already calculated. We check your emissions data, methodology and reduction claims against the GHG Protocol — testing whether the numbers are complete, the data is sound and the conversion factors are current — then show you where to correct them and where to cut emissions.
What a carbon audit is
A carbon audit does not build your footprint from raw data. It scrutinises the footprint you already have — whether that was calculated by your own team in a spreadsheet, produced by carbon software, or delivered by another consultant. Whatever its origin, an audit asks the questions a customer, an auditor or a disclosure reviewer would ask: is anything missing, is the data good enough to stand behind, and has it been calculated the right way?
Because it starts from work that already exists, an audit is narrower and usually quicker than measuring from scratch. If you have never calculated your emissions before, you need a footprint built first — and an audit becomes useful once you have numbers to review.
Building a footprint from scratch is our carbon reporting service. A carbon audit is the confidence check that sits alongside it.
When you need a carbon audit
An audit earns its place at specific moments. The most common are:
You measured in-house and need confidence
Your team calculated the footprint and you want an expert to confirm it holds up before you publish it or share it with a customer.
A customer or tender questioned your numbers
A client, buyer or procurement team has challenged your figures, or asked exactly how they were produced, and you need an independent answer you can stand behind.
You are preparing for verification or disclosure
You are heading into external assurance, a framework such as SECR, or a formal disclosure, and want to find and fix the problems before someone else does.
Your factors or methods are stale
Your last footprint used older conversion factors or an approach that has since moved on, and you need to know whether it is still credible.
What we check
Every audit is tailored to your data, but the review covers the same core ground.
Completeness against the GHG Protocol scopes
We test whether your inventory covers what it should. The GHG Protocol splits emissions into Scope 1 (direct emissions from sources you own or control), Scope 2 (indirect emissions from the electricity, heat, steam or cooling you buy) and Scope 3 (the 15 categories of other indirect emissions across your value chain). We look for scopes or categories left out without a stated reason.
Boundary and consolidation
We check that your organisational boundary is set on a consistent basis — most UK SMEs use operational control — and applied the same way across every site and emissions source.
Data quality
We review where each figure came from. Spend-based estimates are quick but crude and are meant for screening; activity data such as kWh, litres, kilometres and tonnes, and supplier-specific data, are far more reliable. We flag where weak data is doing load-bearing work.
Emission factors and their currency
We confirm you have used the right conversion factors for the right year. The UK Government (DESNZ) updates its greenhouse gas conversion factors annually — the 2026 set was published in June 2026 — and using an out-of-date set, or mismatching it to your reporting year, is one of the most common errors we see.
Scope 2 reporting method
Where it applies, we check that purchased electricity is reported on both a location-based and a market-based basis, as the GHG Protocol requires in markets like the UK.
Methodology and claims
We check the calculations behind the headline figure, and test that any public claims — a reduction percentage, a like-for-like comparison, a neutrality statement — are genuinely supported by the data.
What you receive
You come away with more than a verdict:
A findings report
A clear written report setting out what we reviewed, what stands up, what does not, and how material each issue is.
Corrected baseline guidance
The specific adjustments needed so that future years compare fairly against a sound starting point.
Prioritised reduction opportunities
A shortlist of the reductions your data reveals, ordered by likely impact — because the review shows where your emissions actually sit.
A readiness view
An honest assessment of whether your numbers are strong enough for the tender, disclosure or verification you have in mind.
How a carbon audit works
Share what you have
You tell us what you measured and why, and send us your footprint, workings and source data.
Independent review
We work through your data, methodology and factors against the GHG Protocol and the current UK conversion factors.
Findings report
We set out what we found, with every issue rated and explained in plain English.
Next steps
We talk you through the corrections and the reduction opportunities — and where it helps, we can rebuild the baseline for you.
We have been measuring, reviewing and reporting carbon footprints for UK organisations since 2007.
Carbon Managers have been a trusted partner to Brunel Pension Partnership, bringing strong technical expertise and clear, actionable insight on carbon data metrics and reporting. Their collaborative approach and high-quality delivery strengthened our ability to account and disclose our emissions usage over the past four years, supporting the formulation and delivery of our Carbon Reduction Plans. We valued this partnership and would highly recommend their services.
David Anthony
Head of Finance, Brunel Pension Partnership
We’ve worked with Carbon Managers for several years and have consistently had a positive experience. This year, Joe Venables supported us on our carbon footprint reporting and was excellent throughout—diligent, highly professional, and proactive at every stage. He brought real clarity to the process, helping us strengthen our data collation and understanding, and provided practical, achievable recommendations to enhance our future reporting and accuracy. Despite a tight deadline, Joe delivered on time and was a pleasure to work with throughout.
Angela Dillon
Managing Director, Vanguard Healthcare Solutions
We highly recommend Carbon Managers. Will and Joe guided us through measuring our carbon footprint with exceptional attentiveness and support at every step. They made a complex process seamless, and the end data we received was clear, thorough, and well presented. We couldn’t be happier with the experience.
James Slinger AISEP
Risk and Governance Manager, Blackmore UK
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At Carbon Managers, we provide on-going consultancy and support to our clients from around the world, helping them stay on track with their sustainability goals
Carbon audit FAQs
What is the difference between a carbon audit and a carbon footprint?
A carbon footprint is the calculation of your emissions; a carbon audit is an independent review of that calculation. If you have never measured your emissions, you need a footprint built first, which is our carbon reporting service. If you already have a footprint and want to know whether it is complete, accurate and defensible, you need an audit.
How long does a carbon audit take?
It depends on the size of your organisation and the state of the data, but because an audit reviews work that already exists, it is usually quicker than building a footprint from scratch. Once we have seen your data we will give you a realistic timeline before you commit to anything.
What do you need from us?
Your existing footprint or emissions report, the workings behind it such as spreadsheets or software exports, and the underlying source data — energy bills, mileage, spend and supplier information. The more of that trail you can share, the more thorough the audit can be.
Do we need a carbon audit every year?
Not necessarily. Many organisations audit at key moments — before a first disclosure, when a customer or tender challenges their numbers, or after a change in method — and simply measure in the years between. Because the UK conversion factors change every year, it is worth reviewing your approach periodically even if you do not commission a full audit annually.
Is a carbon audit the same as third-party verification?
No. Accredited third-party verification is a formal process carried out by an approved body against a standard such as ISO 14064-3. A carbon audit is our own independent expert review of your data and methodology. It is often the sensible step before verification, because it finds and fixes the issues an assurer would flag, but it is not itself accredited assurance.
Get a second opinion on your carbon data
Send us your footprint and we will tell you what holds up, what to fix, and where to cut — independent, plain-English and grounded in the GHG Protocol.
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