Carbon Footprint for UK SMEs: A Consultant's Plain-English Guide

Why I'm writing this

I've measured carbon footprints for a catering equipment importer, an NHS healthcare supplier, and a premium gin distillery. Three completely different businesses, three completely different supply chains — and all three came to me with the same question on the first call:

"What actually is a carbon footprint, and what number am I supposed to give the procurement team?"

Most articles on this topic are written for everyone and therefore for no one. They explain the concept in the abstract, list Scope 1, 2 and 3, and stop. That's fine if you're a sustainability student. It's useless if you're a UK SME with a tender deadline and a finance director asking what this is going to cost.

This guide is the answer I give clients on the first call. It's written specifically for UK SMEs — companies between roughly 10 and 250 employees who need a credible footprint, usually because a customer, the NHS, or a government tender is asking for one. No jargon, real numbers, and a few opinions you won't find in the generic explainers.

What a carbon footprint actually is (in one paragraph)

In plain English: it's a single number — measured in tonnes of CO₂ equivalent (tCO₂e) — that represents one year of your company's climate impact. Everything your business burns, buys, or ships contributes to it.

For a UK SME, "everything" usually means:

• Fuel for delivery vans and company cars
• Electricity powering your office, warehouse or factory
• Gas heating your buildings
• Goods and services bought from suppliers (this is usually the biggest chunk)
• Business travel and employee commuting
• Waste sent to landfill, incineration or recycling

CO₂e (carbon dioxide equivalent) is the standard unit because some greenhouse gases — methane, refrigerants — are far more warming than CO₂ per kilo. Converting everything to CO₂e lets you add it all up on one scale.

Scope 1, 2 and 3 — explained for SMEs

The Greenhouse Gas Protocol splits emissions into three categories ("scopes"). The categories matter because tenders, the NHS and SECR all reference them by name.

Scope 1: things you burn directly

• Diesel and petrol in company-owned vans, cars and forklifts
• Gas burned in your boilers and process equipment
• Refrigerant top-ups in air conditioning and chillers

For most UK SMEs Scope 1 is small — typically under 15% of the total — unless you're a manufacturer or run a fleet.

Scope 2: electricity you buy

• Grid electricity for your offices, warehouses and machinery
• District heating or cooling, where applicable

Scope 2 is the easiest scope to measure — your electricity bill literally tells you the kWh — and the easiest to reduce, by switching tariff or installing solar.

Scope 3: everything else (and where the trouble lives)

• Goods and services bought from suppliers (purchased goods)
• Inbound and outbound logistics
• Employee commuting and homeworking
• Business travel by car, train and plane
• Waste disposal and water
• End-of-life treatment of products you sell

The honest truth: for almost every UK SME I've measured, Scope 3 is 70–90% of the total — and it's also the bit no one wants to talk about, because it requires data you don't currently have. If a consultant quotes you a "Scope 1 and 2 only" footprint for a tender, walk away. Procurement teams know what's missing.

Why a UK SME actually needs one in 2026

In my experience, SMEs don't measure their carbon footprint because of polar bears. They measure it because someone with a chequebook is asking. There are three pressures driving almost every enquiry I take:

1. PPN 06/21 — the £5m central government rule

PPN 06/21 requires any supplier bidding for central UK government contracts above £5m to publish a Carbon Reduction Plan — and that plan needs a credible carbon footprint behind it. The footprint is the foundation; the Carbon Reduction Plan is the document they score.

2. The NHS Net Zero Supplier Roadmap

The NHS Net Zero programme has a published timetable: from April 2027, suppliers bidding for NHS contracts above £5m will need a Carbon Reduction Plan covering all emissions; from April 2028 the same applies to all NHS procurement. If you sell to a Trust, you are already in scope.

3. Customer-driven Scope 3 requests

Large UK customers — supermarkets, banks, telcos, manufacturers — are now legally exposed under SECR and increasingly under TCFD. To report their own Scope 3, they need numbers from their suppliers. That's you. The questionnaires are getting longer every year, and "we don't measure that" is starting to cost contracts.

Cost savings and brand reputation are real benefits — but in the SME segment, they're rarely the trigger. Compliance and customer pressure are.

What a typical UK SME carbon footprint actually looks like

Generic guides quote enterprise-scale numbers that are useless for benchmarking. Here are the rough ranges I see across the SMEs I've worked with — drawn from real measured footprints, anonymised by sector.

Catering equipment importer (~50 staff, single warehouse)

Around 180 tCO₂e per year. Scope 1 and 2 are small (gas heating, warehouse lighting, a couple of vans). The dominant chunk — over 70% — is Scope 3 from the manufactured equipment imported from overseas. The lever isn't lighting; it's supplier selection and shipping mode.

NHS healthcare supplier (~80 staff, two sites)

Around 300–350 tCO₂e per year. Scope 2 is meaningful because of medical-grade storage. Scope 3 is dominated by single-use plastic products and inbound logistics. For NHS framework agreements, every line item on the product portfolio gets scrutinised.

Premium spirits distillery (~25 staff)

Around 90–110 tCO₂e per year. Scope 1 is non-trivial because of distillation gas. Scope 3 is dominated by glass bottles — heavy, fragile, energy-intensive to manufacture. Most of the reduction conversation is about packaging weight and supplier location, not heating.

For a real example, see our 6 O'Clock Gin case study — a UK distiller whose verified footprint highlighted glass packaging as the largest reducible category, and who used the result to support trade and retailer disclosures.

Office-only professional services firm (~10–30 staff)

Typically 25–60 tCO₂e per year. Scope 1 is often zero. Scope 2 is small. Scope 3 is mostly commuting, business travel, IT equipment and cloud services. These footprints are quick to measure but harder to reduce, because the levers are HR policy and procurement choices, not capex.

For a sector-by-sector view of what we measure for clients, see our carbon consultancy service page.

If you'd rather scope your own footprint before talking to a consultant, our free Company Carbon Survey walks you through the data points an SME footprint typically needs. For a consultant-led version, see our Carbon Footprint Assessment service, or jump straight to transparent pricing.

Three things UK SMEs get wrong about carbon footprints

After several years of doing this, the same patterns repeat. If you're about to start, save yourself the detour.

1. Buying a calculator before you understand Scope 3

The market is full of low-cost calculators that focus on Scope 1 and 2 because that data is easy. SMEs run their numbers, get a small comforting figure, send it to a procurement team and get rejected — because the procurement team knows the supply chain (Scope 3) is missing. Understand the scope before you pick the tool. Don't pay for a number that won't be accepted.

2. Treating it as a one-off project

A carbon footprint is a baseline, not a deliverable. PPN 06/21 and the NHS framework explicitly require year-on-year reporting against that baseline. If you measure once and don't repeat the exercise next year, the original footprint becomes worthless 12 months in. Budget for an annual refresh from day one.

3. Confusing "carbon neutral" with "net zero"

These are not synonyms. "Carbon neutral" usually implies offsetting; "net zero" implies deep reduction first, with offsets only for residuals. Putting the wrong claim on a tender response, a website, or a product label is now a live legal risk under the CMA Green Claims Code. Get the language right before you publish anything.

How to actually measure it (the three-step version)

Stripped of jargon, the process every credible footprint follows is the same — using official DEFRA emission factors for the UK.

1. Collect 12 months of data. Energy bills (kWh of electricity and gas), fuel receipts or fuel-card data, mileage logs, business travel, waste invoices, and spend or activity data on purchased goods and services. For SMEs, the bottleneck is almost always purchased goods.
2. Apply emission factors. Each unit of activity gets multiplied by a DEFRA factor to convert it into kg CO₂e. UK grid electricity is around 0.207 kg CO₂e per kWh in the 2024 factors; natural gas is around 0.18 kg CO₂e per kWh. The factors are updated every June — use the current year's set.
3. Total and split by scope. Sum the results, divide them across Scope 1, 2 and 3, and present them in tonnes CO₂e. That single, scoped number is your carbon footprint and the baseline for everything that follows.

The maths is genuinely simple. The hard part is the data quality on Scope 3 — which is why most SMEs eventually outsource it rather than burn three months of finance team time chasing supplier spreadsheets.

Carbon footprint vs Carbon Reduction Plan — they are not the same thing

This is the single most common point of confusion in tender season. They get used interchangeably; they are not interchangeable.

• Carbon footprint: the measurement. A number in tCO₂e, broken down by scope, for a defined 12-month period. It's the data.
• Carbon Reduction Plan (CRP): the document. A board-signed-off plan that uses the footprint as a baseline, commits to net zero by 2050 (or earlier), states current-year emissions, and lists the projects you'll deliver to get there. It's what procurement actually scores under PPN 06/21.

You can't write a credible CRP without a footprint, and a footprint on its own won't pass PPN 06/21 scoring. For tender bids, plan to deliver both — see our Carbon Reduction Plan service for what a compliant plan needs to include.

What to do once you have your footprint

The number itself isn't the deliverable. It's the starting point for three follow-on workstreams.

Build a reduction strategy that prioritises by impact

Don't start with the easy stuff. Start with the biggest line in the footprint. For most SMEs that's a Scope 3 category — purchased goods, logistics or commuting — and it's where the meaningful reductions live. LED lighting is a nice-to-have; switching a high-emission supplier or moving from air to sea freight is the actual lever. Our carbon consultancy team works through this prioritisation with clients.

Use the data in tenders, not just reports

The footprint becomes content for PPN 06/21 responses, NHS framework bids, ESG sections of RFPs, and customer questionnaires. Turn it into a one-page summary your sales team can attach to bids without asking finance every time.

Offset residuals — but only after reduction

Carbon offsetting has a legitimate role for residual emissions you genuinely can't reduce yet. It is not a shortcut to a "carbon neutral" claim. The CMA's Green Claims Code and the SBTi guidance both make this clear: reduce first, offset what's left.

Frequently Asked Questions