For an office-based firm, most of the carbon is travel and purchased services
Most office-based firms first look at their footprint when a client or a tender asks for it. The answer is almost entirely Scope 3, dominated by business travel, then the cloud and the suppliers they pay. It can be built from the expense and supplier records already on file.
You stay the reviewer
Expense and utility data in, a defensible number out
The inputs are easy enough to find: an office power bill, travel booked through expenses, cloud invoices, and spend on contractors. The analyst matches each to the right factor and produces a footprint you can put in front of a client or a tender with confidence.
Emissions line
Grid electricity, head office, quarter
Result
99 t CO₂e
How the analyst got there
Source
Retailer invoice, 150,000 kWh
Emission factor
NGA 2025, NSW Scope 2: 0.66 kg CO₂e/kWh (location-based)
Reasoning
Purchased electricity → Scope 2. Activity-based: metered kWh.
Bringing experience with SME to Enterprise
99.95%
Calculation accuracy
Scope 3 led
Emissions profile
30 min
Average processing time
Every number traced to sourceSee a finished inventory, every number traced to its source
A completed, ASRS-ready example. Every figure linked back to its source document, emissions factor, and reasoning.
Tell us about your team and we'll walk you through this example.
How it works
Drop in office energy, travel expenses, cloud invoices and contractor spend, the analyst calculates each scope with matched factors, and you report per office, per practice or consolidated across the firm.
See the full process →Scope 3 · Category 6
Business travel
For most firms, flights are the single largest line, often larger than the office itself. CO2 Lab reads travel from expenses or your travel agent, applies distance and cabin factors, and makes the dominant part of the footprint visible rather than an afterthought.
Flights by distance and cabin class
Accommodation and ground travel
From expense and travel-agent data
Primary and default data clearly labelled
Office electricity by state NGA factor
Cloud and data-centre services
Working-from-home energy, Scope 3 Category 7
Location-based and market-based reported
Scope 2 & 3 · Office and cloud
Office and cloud
The office power is your Scope 2, and the cloud you run on and your people working from home are Scope 3. CO2 Lab reads the office meter, estimates cloud and home-working on recognised bases, and labels each so the small on-site footprint is not mistaken for the whole picture.
Scope 3 · Category 1
Purchased services
Subcontractors, IT, marketing and professional fees are the rest of a firm's footprint. CO2 Lab starts from spend with spend-based factors, swaps in supplier data as it arrives, and labels every line so you can see what is estimated and what is real.
Subcontractor and professional fees
IT, software and marketing spend
Spend-based estimate to start, labelled
Reconciled so nothing is counted twice
Frequently asked questions
The Scope 3 number a client will ask you for
A free 30-minute chat, no obligation, on where you stand ahead of your first client or tender request.
Book a Sustainability Check-upWhere to go next
Consultants
Delivering carbon work for clients, with the working shown.
MethodologySpend vs activity-based
Which method to use where, and why it changes your Scope 3.
MethodologySupplier engagement
Replace spend estimates with real supplier data.
ComplianceASRS by group
Your reporting group, start date and disclosure requirements.