How to Calculate Scope 1 Emissions
Step-by-step guide to measuring your direct greenhouse gas emissions from owned or controlled sources.
In this guide
What Are Scope 1 Emissions?
Scope 1 emissions are direct greenhouse gas (GHG) emissions from sources that are owned or controlled by your organisation. Under the GHG Protocol Corporate Standard, these are emissions that occur from sources within your organisational boundary.
Common Scope 1 sources include combustion of fuels in company-owned boilers and furnaces, company-owned vehicles (fleet cars, vans, trucks), fugitive emissions from air conditioning and refrigeration systems, and process emissions from manufacturing operations.
Step 1: Identify Your Scope 1 Sources
Create a comprehensive inventory of all emission sources your organisation owns or controls:
• Stationary combustion: natural gas boilers, oil-fired heating, backup generators, on-site cooking equipment • Mobile combustion: company-owned or leased vehicles — cars, vans, trucks, forklifts • Fugitive emissions: refrigerant gases from air conditioning, cold storage, heat pumps • Process emissions: chemical reactions in manufacturing (e.g., cement, steel, glass production)
Step 2: Collect Activity Data
For each Scope 1 source, collect the activity data for your reporting period:
Natural gas: kWh from gas bills. Transport fuel: Litres of petrol, diesel, or LPG from fuel card statements. Refrigerants: kg of refrigerant topped up during the year. Other fuels: Litres of heating oil, kg of LPG, tonnes of coal.
Step 3: Apply Emission Factors
Multiply each activity data point by the appropriate DEFRA emission factor. DEFRA publishes updated factors annually (usually in June) in the "Government GHG Conversion Factors" spreadsheet.
Step 4: Sum and Report
Add up all your Scope 1 emissions to get a total in tCO₂e (divide kgCO₂e by 1,000). Break this down by source type for transparency.
Key Takeaways
Related Guides
Frequently Asked Questions
It depends on the lease type and your organisational boundary approach. Under operational control, vehicles you operate day-to-day (even if leased) are Scope 1.
Use the best available proxy. For fleet, mileage data with DEFRA distance-based factors is acceptable.
Upload your raw fuel bills, gas invoices, and vehicle data. Climatise automatically maps the data to the correct emission sources, applies the right DEFRA factors, handles unit conversions, and produces an auditable Scope 1 breakdown with full traceability to source records.
Want us to handle this for you?
Climatise handles the data collection, calculations, and reporting covered in this guide. See it in action.
Book a Demo →