How to Calculate Your Business's Carbon Footprint (Step by Step)

To calculate your business carbon footprint, add up your emissions across three scopes — Scope 1 (direct), Scope 2 (purchased energy) and Scope 3 (value chain) — converted into tonnes of CO₂e using standard emission factors. Most small businesses can produce a solid first estimate in an afternoon using bills and records they already keep; the harder part is Scope 3, which usually dominates the total.

What a business carbon footprint includes

• Scope 1 — direct emissions from sources you own or control: company vehicles, gas boilers, on-site generators and refrigerant leaks.
• Scope 2 — purchased energy you buy and consume, mainly grid electricity, plus any district heating or cooling.
• Scope 3 — everything else in your value chain: purchased goods and services, business travel, employee commuting, waste, shipping and the use of products you sell.
• The 80% rule — for most SMEs, Scope 3 makes up the large majority of total emissions, so ignoring it badly understates your footprint.

The steps to measure it

Work through five practical steps. First, set your boundaries — decide which sites, subsidiaries and scopes you are counting and pick a 12-month reporting period. Second, gather activity data: litres of fuel, kWh of electricity, miles travelled, kilograms of waste. Third, apply emission factors that convert each activity into CO₂e (a kWh of electricity, for example, carries a factor tied to your national grid mix). Fourth, total everything in tonnes CO₂e so the different gases and sources sit on one comparable scale. Fifth, sanity-check the result against a per-employee or per-revenue benchmark. If you want a shortcut for the first pass, the free Evertreen CO₂ calculator turns a few inputs into an estimate you can build on.

Data sources SMEs already have

• Utility bills give you kWh of electricity and gas straight from your supplier — the backbone of Scopes 1 and 2.
• Fuel and mileage records from fuel cards, expense claims and vehicle logs cover fleet and business travel.
• Purchase ledgers and supplier invoices feed a spend-based estimate of Scope 3 when you lack supplier-specific data.
• Waste and courier accounts report tonnage and shipments you can convert with published factors.
• HR and payroll data gives you headcount and home postcodes for a commuting estimate, plus the per-employee denominator for benchmarking.

A worked example: a 25-person office business

Numbers vary enormously by sector, so treat this as a shape rather than a benchmark. A typical service business with one leased office might find:

• Scope 1 — a couple of company cars and a gas boiler: a handful of tonnes.
• Scope 2 — office electricity from the bills: often in the low tens of tonnes, and frequently the easiest to cut to near zero on paper with a renewable tariff.
• Scope 3 — purchased goods and services, cloud and software, professional services, commuting, business flights: routinely several times Scopes 1 and 2 combined.

The lesson almost every first calculation teaches is the same one: the emissions are not where people expect. Teams who assumed it was the office lighting usually find it is procurement and flights.

Screening Scope 3 without drowning in it

The GHG Protocol splits Scope 3 into fifteen categories, and trying to measure all of them properly in year one is the most reliable way to abandon the project. Do this instead:

1. Screen everything roughly using spend data — multiply each purchase-ledger category by a published spend-based factor.
2. Rank by size and identify the two or three categories that carry the bulk of the total.
3. Measure those properly with activity data or supplier-specific figures.
4. Disclose the rest as screened estimates, stating the method.

Spend-based data has one important weakness worth understanding before you rely on it: it barely moves when a supplier decarbonises. Buy the same value of goods from a cleaner manufacturer and your reported number stays flat. That is why the top suppliers should migrate to activity-based data over time — the detail is in Scope 3 emissions and carbon offsets.

Five mistakes that invalidate a first footprint

• Changing the boundary between years. If you add a site or a category, restate the baseline — otherwise your "reduction" is an accounting artefact.
• Reporting only one Scope 2 method. The GHG Protocol expects both location-based (grid average) and market-based (what you contracted for). A renewable tariff moves only the second.
• Forgetting refrigerants. Air-conditioning and refrigeration leaks are Scope 1 and carry very high warming factors for small quantities.
• Double counting. Fuel claimed both as mileage and as a fuel-card litre is a classic; so is counting a courier's emissions in both shipping and purchased services.
• Using last decade's factors. Grid factors change every year. Date-stamp the factor set you used.

Reduce first, then offset the rest

Measuring is only the start — the credible order is to cut what you can, then offset the residual you cannot yet eliminate. Switch to a renewable electricity tariff, cut business travel, improve building efficiency and lean on lower-carbon suppliers before you buy anything. For the emissions that remain, you can compensate transparently: Evertreen lets you plant trees from £1.5 each, every one geolocated with a GPS pin and progress photos, backed by on-the-ground field videos from planting teams. Because trees take years to sequester carbon, we are honest that planting is a long-term removal, not an instant cancellation — our method for estimating tree CO₂ shows exactly how the numbers are derived. For practical reduction ideas, see how to reduce your carbon footprint.

When you need certified credits

If you are reporting formally or want independently audited removals, tree planting can sit alongside verified carbon credits. Evertreen offers certified Verra and Gold Standard carbon credits on request, so finance and sustainability teams can back claims with recognised standards. Featured in 300+ media outlets and available via API and Shopify integration, the platform lets you build offsetting into your operations once you know your number — and keep tracking it year over year.

One caution on how you describe the result: under the SBTi corporate net-zero standard, purchased credits do not count towards emission-reduction targets, and from 27 September 2026 the EU restricts marketing a product to consumers as carbon neutral on the basis of offsetting. Report the reduction and the compensation as two separate numbers — it is both more accurate and easier to defend. See are carbon offsets greenwashing?

Frequently asked questions

What is a business carbon footprint calculator? It is a tool that converts your activity data — energy use, fuel, travel and spend — into total tonnes of CO₂e across Scopes 1, 2 and 3, giving you a single figure to track and reduce.

How long does it take to calculate a small business footprint? A first estimate using utility bills, mileage and purchase records typically takes a few hours; a thorough Scope 3 assessment with supplier data can take several weeks.

Should I reduce emissions or offset them first? Reduce first — cut what you realistically can through energy, travel and supplier changes, then offset only the residual emissions you cannot yet eliminate.

Do I have to measure all fifteen Scope 3 categories? No. Screen all fifteen roughly, measure the material ones properly, and disclose which categories were estimated or excluded and why.

Which emission factors should I use? Use a recognised published set appropriate to your country and update them annually, recording which version you applied so year-on-year comparisons stay honest.

Do I need an external consultant or auditor? Not for a first internal estimate. Verification becomes relevant when you publish claims, respond to customer questionnaires or fall under a reporting regime.

How often should I recalculate? Annually, with the same boundary and a restated baseline whenever the boundary changes — otherwise the trend line means nothing.