Measure if it helps you. Skip it if it doesn't.
Most platforms make measurement the gate you have to pass before you are allowed to do anything. That has stopped more small businesses from acting than it has ever helped. So here it is a tab, not a turnstile: use it when you want a target to aim at, ignore it when you just want to buy a round number of tonnes.
The simple estimate
Ten minutes, eight buckets, no bills required. It follows the method Basecamp published when they footprinted themselves: split the business into fewer than a dozen likely drivers, use real activity data where you have it, use spend as a stand-in where you don't, then add explicit wiggle room rather than pretending the answer is exact — and round up.
The point is not precision. It is getting a defensible number today so you can act, and learning which single line to improve next. For most small businesses that is the entire value of measuring, and the remaining precision costs a consultant.
What you need to hand
Headcount, roughly how often people are in the office, how many flights the team took, and your annual spend on cloud, software and everything else. That is it. Electricity bills help but are not required — we fall back to floor-area benchmarks.
The eight buckets
- 1How the team works
- 2Office energy
- 3Travel
- 4Stays & meetups
- 5Hardware
- 6Cloud & software
- 7Everything else you buy
- 8Wiggle room
The last one is the honest one. A first estimate always misses something, so rather than quietly under-count we add a visible allowance — 10% by default — and round the total up to a whole tonne, because you cannot buy a fraction of a credit and erring high is the right direction to err.
The full inventory
A GHG Protocol Corporate Standard footprint across all three scopes, built from your own activity data using DEFRA/DESNZ 2026 conversion factors at IPCC AR5 GWP-100. Use this when someone is going to check your working: a customer's procurement team, a B Corp assessor, or a reporting requirement you have taken on.
Every line shows its own arithmetic — the quantity, the factor and the source — and is tagged as either activity data or an estimate, so you can see exactly how much of your number rests on real measurement.
Scope 1
Fuel you burn
Gas, heating oil and LPG in buildings you control, petrol and diesel in vehicles you own or lease, and refrigerant top-ups from servicing invoices.
Scope 2
Energy you buy
Purchased electricity, district heat and EV charging on your own meters. Certified renewable supply is reported market-based, and we show the grid-average figure alongside it so you can disclose both.
Scope 3
Everything else
Purchased goods and services, capital equipment, waste and water, business travel, and commuting and home working. The well-to-tank uplift on your fuel and electricity is derived from your Scope 1 and 2 answers rather than asked for.
Tailored to a few sectors, not everyone at once
A catch-all calculator asks a drinks brand about cloud spend and a software company about refrigeration, and both give up. We started with the sectors that dominate the small businesses actually buying credits — and the UK B Corp register in particular.
Software & SaaS
SaaS products, dev shops, app studios, data and AI companies
Product and engineering businesses whose footprint lives in cloud compute, laptops and the way the team works and travels.
Typically 2–10 tCO₂e per employee per year.
Professional services & agencies
Consultancies, creative and marketing agencies, law and accountancy firms, architects
People businesses that bill time. Offices, business travel and the services you buy in are what matter.
Typically 1.5–9 tCO₂e per employee per year.
Food & drink brands
Drinks brands, snack and food producers, coffee roasters, bakeries, speciality retailers
Brands making or selling food and drink. Ingredients, packaging, refrigeration and distribution carry the footprint.
Typically 8–50 tCO₂e per employee per year.
| Sector | tCO₂e per employee | Scope 1 | Scope 2 | Scope 3 |
|---|---|---|---|---|
| Software & SaaS | 2–10 (mid 4.5) | 2% | 8% | 90% |
| Professional services & agencies | 1.5–9 (mid 3.8) | 5% | 15% | 80% |
| Food & drink brands | 8–50 (mid 18) | 12% | 13% | 75% |
| Something else | 2–25 (mid 6) | 15% | 15% | 70% |
Ranges are indicative and used to sanity-check your own answer, not to replace it. If your number lands outside the range for your sector we say so, because that is usually a missing category or a unit mix-up rather than a genuinely unusual business. Per-employee comparison is misleading for food and drink — compare against revenue there instead.
Save it, come back to it, lock it in
Nobody finishes a footprint in one sitting, and a form that loses your answers when you go to find an electricity bill is a form you never come back to. So every measurement is saved per year and stays editable indefinitely.
Saved by year
One simple estimate and one full inventory per year, kept separately, so you can watch the number move over time and see whether the changes you made worked.
Draft until you say otherwise
Stop halfway and the total so far is waiting when you return, along with your notes about what you had to guess and what to chase up next time.
Lock it in when you are happy
Crystallising a year marks it as the number you will stand behind. It becomes the target on your dashboard and pre-fills your next purchase, so getting to net zero for that year is one click.
Both kinds can coexist
Keep a quick estimate and a full inventory for the same year. When they disagree we use the inventory, because activity data beats spend proxies — and a locked-in year beats a draft.
Get a number in ten minutes
Or don't. Both routes end in the same place: credits retired in your name, with proof you can share.