Scope 1, 2 & 3 Emissions Explained for Small Business
If a client, enterprise customer, or partner has asked your business for Scope 1, Scope 2, or Scope 3 emissions, you're probably wondering what these terms actually mean, and what you're expected to submit.
This guide explains emissions scopes in simple terms and shows how small businesses can generate a defensible carbon footprint estimate without complex tracking systems.
Why small businesses are being asked for emissions data
Large companies are under pressure to report full carbon footprints. That includes emissions from their suppliers and partners.
California's SB-253 requires companies with more than $1 billion in revenue that do business in California to report Scope 1 and 2 emissions, with the first reports due 10 November 2026, and Scope 3 from 2027. In the EU, after Directive (EU) 2026/470, the CSRD applies to companies with more than 1,000 employees and more than EUR 450 million turnover, from FY 2027. Most SMEs are outside it, but those large companies may still ask their suppliers for data. Through CDP, more than 200 organizations requested environmental data from over 45,000 suppliers in 2025.
When a large customer reports Scope 3, it either estimates its suppliers' emissions from what it spends with them or asks the suppliers directly. Your own figure, built from your actual fuel, electricity and purchases, lets them replace that industry-average estimate with a supplier-specific one.
So even if you're a small company, you may receive requests for Scope 1, Scope 2, and Scope 3 emissions.
This usually happens during:
- Supplier onboarding
- ESG questionnaires
- Contract renewals
- Sustainability reporting
Most small businesses don't track emissions, and that's expected.
What are Scope 1, 2, and 3 emissions?
These categories come from the GHG Protocol, the global standard used for carbon reporting. They divide emissions into three simple groups.
Scope 1 emissions (direct emissions)
These are emissions from sources your business directly controls.
Examples:
- Fuel used in company vehicles
- Diesel or gas generators
- On-site fuel combustion
- Manufacturing fuel use
- Refrigerant leaks from air conditioning or refrigeration units
If your business buys fuel directly, that usually falls under Scope 1. Most service-based companies have low Scope 1 emissions.
Scope 2 emissions (energy emissions)
These come from purchased energy. You aren't burning anything on-site, but the power plant providing your electricity is.
Examples:
- Electricity for office or facility
- Purchased heating or cooling
- Utility energy use
If your business pays electricity bills, you likely have Scope 2 emissions. For many SMEs, Scope 2 is one of the largest emission sources.
Scope 3 emissions (value chain emissions)
Scope 3 includes indirect emissions across your business activities. They occur both upstream (from your suppliers) and downstream (from your customers).
Common Scope 3 categories for small businesses:
- Shipping and logistics
- Cloud services and software
- Purchased goods and services
- Business travel
- Waste disposal
Large enterprises often ask suppliers for Scope 3 data because it forms a major part of their total footprint. CDP's global supply chain report Transparency to Transformation (February 2021) found that, among the companies it analyzed, supply chain emissions were on average 11.4 times as high as operational emissions. You are usually not expected to calculate all 15 Scope 3 categories, just reasonable estimates.
Two illustrative examples
Here is how the three scopes look for two typical small businesses.
Illustrative example (fictional company): a marketing agency
- Scope 1: They have no company cars and use a central HVAC system. Their Scope 1 is nearly zero, except for some minor refrigerant leakage from a server room AC unit.
- Scope 2: They pay for electricity for their two-floor office. By looking at their utility bills, they can calculate exactly how many kilowatt-hours (kWh) they used and apply a local "grid factor."
- Scope 3: This is where most of their footprint sits: software and office supplies (Category 1: Purchased Goods and Services), the laptops they bought (Category 2: Capital Goods), the flights their team took for client pitches (Category 6: Business Travel), and staff commuting (Category 7: Employee Commuting, where the GHG Protocol Scope 3 Standard lets companies include home working).
Illustrative example (fictional company): a small food manufacturer
- Scope 1: They have a fleet of delivery vans and a natural gas-powered oven. This is a significant Scope 1 footprint.
- Scope 2: High electricity usage for industrial refrigeration.
- Scope 3: Large emissions from the raw ingredients (flour, sugar, packaging) purchased from farmers and suppliers.
What is CO2e?
Not all greenhouse gases are created equal. Methane (CH4) is much more potent than carbon dioxide (CO2). To make reporting simpler, every gas is converted into a single unit called carbon dioxide equivalent (CO2e), using its global warming potential. Under the IPCC's Fifth Assessment Report, for example, one kilogram of the common refrigerant R-410A counts as 1,924 kg CO2e over 100 years. This lets you report one number that covers everything from your vehicle exhaust to your office air-conditioning leaks.
Do small businesses need exact data?
No. Most SMEs do not track:
- Fuel consumption in liters
- Electricity in kWh
- Supplier emission data
That's why the GHG Protocol's Scope 3 calculation guidance includes a spend-based method for when activity data isn't available, and fuel or electricity spend can be converted to liters or kWh at published prices. It is a common method for suppliers responding to ESG requests.
How small businesses typically calculate emissions
Instead of tracking every activity, companies use financial data.
Example:
- Electricity spend → mapped to emission factor
- Fuel spend → mapped to emission factor
- Logistics spend → mapped to emission factor
This produces a reasonable estimate aligned with accepted standards. Many supplier questionnaires accept this approach, provided you state the method and the factors used.
Expect a wide margin. Spend-based screening carries roughly +/-25-40% uncertainty at the category level. That band is our engineering estimate; the GHG Protocol publishes no figure.
When Scope 3 is required
Under the GHG Protocol Corporate Standard, companies report Scope 1 and 2 at a minimum, and Scope 3 is optional. In practice, it depends on who is asking.
You may be asked for Scope 3 if:
- You supply a large enterprise
- Your client reports ESG data
- You're part of a global supply chain
- A sustainability questionnaire asks for value-chain emissions
In many cases, providing top Scope 3 categories is enough.
The biggest mistake to avoid
Many small businesses either:
- Leave emissions fields blank
- Guess numbers
- Delay responses
This creates procurement risk. Enterprises don't expect perfection. They expect a documented estimate with clear methodology.
Generate your Scope 1, 2, and 3 emissions draft in minutes
AI Sustainable Future helps small businesses create a defensible carbon emissions draft using annual spend data. No consultants. No complex tracking. No manual calculations.
Choose your draft
Basic (Scope 1 and 2), $20
- Direct and energy emissions
- Spend-based, with optional kWh and fuel volumes you enter
- Supplier-ready PDF
- Every emission factor cited to its source
Complete (Scope 1, 2 and Scope 3), $49
- Adds up to 8 of the 15 Scope 3 categories: purchased goods and services, capital goods, upstream transport, waste, business travel and employee commuting where your ledger has spend in them, fuel- and energy-related emissions from your electricity, and end-of-life of sold products when you enter tonnages
- Designed for ESG and supplier requests
- Clear assumptions and boundaries
Need every transaction priced with its factor, per-row confidence, an Excel calculation workbook and a framework section for GHG Protocol, CDP, CSRD (ESRS E1) and California SB-253? That is the Disclosure-Aligned Report, $299. See all tiers on the pricing page.
Is this acceptable for ESG questionnaires?
Usually, yes. Many enterprises accept spend-based emissions estimates from small suppliers when detailed activity data isn't available, and California's SB-253 allows reporting companies to use secondary data, such as spend-based industry averages, for Scope 3. Some programs ask for more: Microsoft, for example, asks in-scope suppliers for third-party assurance or a letter from an external consultant.
Your report will:
- Follow GHG Protocol methodology
- Use recognized emission factors, each cited to its source document (see our methodology)
- Include documentation
- Provide a defensible baseline
- Be marked as a screening-grade inventory, not assured: a starting point a reviewer or assurance provider can work from
Generate your emissions draft now
If you've been asked for Scope 1, 2, or 3 emissions and aren't sure how to calculate them, start here. Upload your accounting export at aisustainablefuture.com/carbon-draft and get a cited, screening-grade carbon report in minutes. Scope 1 and 2 from $20, Scope 3 from $49.
