The three scopes divide your emissions into what you control directly, what you pay for indirectly, and what happens because of your products

Scope 1, 2, and 3 emissions are a framework that splits a company's greenhouse gas output into three categories based on where the emissions come from and who causes them. Scope 1 covers emissions your company produces directly — burning fuel in your own vehicles or equipment. Scope 2 covers emissions from electricity, steam, or heating you purchase from outside sources. Scope 3 covers emissions that happen because of your business but occur somewhere else in your supply chain or after customers use your product.

The reason this split matters is practical: you can control Scope 1 by changing your own equipment. You can influence Scope 2 by switching energy suppliers. But Scope 3 often involves dozens of other companies, so you measure it differently and set different reduction targets. Most businesses find that Scope 3 is their largest number — sometimes 5 to 10 times bigger than Scopes 1 and 2 combined — which is why understanding the difference changes how you plan.

Key Takeaways

  • Scope 1 is emissions your company produces directly from sources you own or control, like company vehicles or on-site fuel burning.
  • Scope 2 is emissions from electricity, steam, or heating you purchase, even though the power plant or utility produces them elsewhere.
  • Scope 3 is emissions throughout your supply chain and from customer use of your products — the hardest to measure but often the largest.
  • You measure each scope differently because you have different levels of control: direct data for Scope 1, utility bills for Scope 2, and estimates or supplier data for Scope 3.
  • Most emissions reporting standards require all three scopes, though Scope 3 methods vary widely depending on your industry.

Scope 1: Emissions you produce directly

Scope 1 includes any greenhouse gas emissions from sources your company owns or operates. This covers company vehicles (cars, trucks, delivery vans), equipment that burns fuel (generators, forklifts, boilers), and refrigerants or other gases that leak from your equipment. If your business runs a fleet or heats a building with natural gas, those are Scope 1.

Measuring Scope 1 is straightforward because you have direct access to the data. You track fuel purchases, maintenance records, and equipment specifications. A delivery company counts gallons of diesel purchased. A manufacturing plant measures cubic feet of natural gas burned. A refrigeration company documents refrigerant refills. The emissions factor — how many pounds of CO₂ one gallon of fuel produces — is standardized and published by the EPA and other agencies, so the math is consistent across companies.

Scope 1 is usually the smallest of the three scopes for service businesses and retailers, but it can be the largest for transportation, construction, or agriculture companies. Reducing Scope 1 typically means switching to electric vehicles, upgrading to more efficient equipment, or fixing leaks in refrigeration systems.

Scope 2: Emissions from energy you buy

Scope 2 emissions come from electricity, steam, or heating you purchase from a utility or third party. You do not burn the fuel yourself — the power plant does — but you caused the emissions by using the energy. An office building that buys electricity from the grid counts those emissions as Scope 2, even though the coal or natural gas burned at the power plant miles away.

Measuring Scope 2 requires your utility bills and the emissions intensity of your local power grid. Emissions intensity varies by region because different areas use different fuel sources: a grid powered mostly by wind has lower intensity than one powered by coal. Your utility or a public database (like the EPA's eGRID tool) provides the emissions factor for your region. You multiply your kilowatt-hours by that factor to get your Scope 2 total.

Scope 2 is usually larger than Scope 1 for office buildings, data centers, and retail stores. Reducing it means using less electricity, switching to LED lighting, or purchasing renewable energy credits or power from a utility's green energy program. Some companies sign power purchase agreements with wind or solar farms to may provide their electricity comes from low-carbon sources.

Scope 3: Emissions throughout your supply chain and from product use

Scope 3 is everything else — emissions that happen because of your business but outside your direct control. This includes emissions from suppliers making materials you buy, transportation of goods you do not own, business travel by employees, waste sent to landfills, and emissions from customers using your products. A clothing company's Scope 3 includes cotton farming, fabric dyeing, shipping to stores, and washing by customers. A software company's Scope 3 includes server energy use by customers and employee commuting.

Scope 3 is split into 15 categories by the Greenhouse Gas Protocol, the standard most companies follow. The categories that matter depend on your industry. A retailer focuses on purchased goods and capital goods (manufacturing equipment). A transportation company focuses on business travel and employee commuting. A consumer goods company focuses on product use and end-of-life disposal. You do not measure all 15 — you measure the ones material to your business.

Measuring Scope 3 is harder because you do not have direct data. You use supplier surveys, industry averages, or spend-based estimates. A spend-based estimate multiplies your spending in a category (say, $500,000 on packaging materials) by an emissions factor for that industry (say, 2 pounds of CO₂ per dollar spent). The result is an estimate, not a precise count, which is why Scope 3 methods vary more than Scopes 1 and 2.

Scope 3 is almost always the largest category. For a consumer goods company, it can be 80 to 90 percent of total emissions. Reducing it requires working with suppliers to lower their emissions, designing products to last longer or use less energy, and encouraging customers to use products more efficiently.

Why the three-scope system matters for your reporting

Most emissions reporting standards — including the Greenhouse Gas Protocol, the Science Based Targets initiative, and the SEC's proposed climate disclosure rules — require companies to measure and report all three scopes. But they treat them differently. Scope 1 and 2 are mandatory. Scope 3 is mandatory to report, but the methods are less prescriptive because every industry is different.

The three-scope split also shapes your reduction strategy. Scope 1 reductions come from your own capital investments: buying electric vehicles, upgrading equipment. Scope 2 reductions come from switching suppliers or buying renewable energy. Scope 3 reductions require collaboration with suppliers, customers, and partners — they take longer but often deliver the biggest impact. A company that only reduces Scope 1 and 2 but ignores Scope 3 is missing most of its emissions.

Understanding which scope is largest in your business tells you where to focus. A manufacturing company should prioritize Scope 1 (direct fuel use) and purchased materials (Scope 3). A software company should prioritize Scope 2 (data center electricity) and employee commuting (Scope 3). A retailer should prioritize Scope 3 (products sold and customer use).

How to start measuring your three scopes

Begin with Scope 1 because the data is easiest to find. Gather fuel purchase records, vehicle mileage logs, and equipment maintenance records for the past year. Use EPA emissions factors or your fuel supplier's data to convert gallons or cubic feet into pounds of CO₂. This usually takes one person a few days.

Next, measure Scope 2 using your utility bills. Request the emissions factor from your utility or look it up in the EPA's eGRID database by your region. Multiply your annual kilowatt-hours by the factor. If you buy steam or heating, ask the supplier for their emissions factor.

For Scope 3, start by identifying which categories matter to your business. A manufacturing company might focus on purchased materials and transportation. A retailer might focus on products sold and product use. A service company might focus on business travel and employee commuting. Once you know your categories, decide whether to use supplier data, industry averages, or spend-based estimates. Many companies start with spend-based estimates because they require only financial data, then move to more detailed methods as they mature.

Most companies use software tools or hire consultants to manage this process, but you can start with a spreadsheet and the EPA's emissions factors. The Greenhouse Gas Protocol publishes detailed calculation tools for each scope and industry.

Common mistakes when dividing emissions into scopes

One mistake is double-counting. If you buy electricity from a utility, that goes in Scope 2. Do not also count it in Scope 1 as fuel burned at the power plant — the utility already did. Another mistake is treating Scope 3 as optional. Many companies report only Scopes 1 and 2 because they are easier to measure, but this understates total emissions and makes reduction targets look more ambitious than they are.

A third mistake is using the wrong emissions factor. Scope 2 factors change by region and year as grids add renewable energy. Using last year's factor or a national average instead of your local factor can be off by 30 to 50 percent. A fourth mistake is setting reduction targets without understanding which scope is largest. If Scope 3 is 85 percent of your emissions but you only reduce Scope 1, you will miss your target.

Finally, some companies confuse Scope 3 with corporate social responsibility. Scope 3 is not about voluntary programs — it is about measuring and reducing emissions that happen because of your business, whether or not you directly control them. A company that donates to renewable energy projects but does not measure Scope 3 is not reducing its actual emissions.

Frequently Asked Questions

Is Scope 3 really required, or can I just report Scopes 1 and 2?

Most standards require all three scopes in your inventory, but Scope 3 methods are less strict because they vary by industry. However, if Scope 3 is 80 percent of your emissions and you do not report it, your total is incomplete and your reduction targets are misleading. Investors and regulators increasingly expect Scope 3 data.

How do I measure Scope 3 if I do not control my suppliers?

You use estimates based on spending, industry averages, or supplier surveys. A spend-based estimate multiplies what you paid for a category by a published emissions factor for that industry. It is less precise than direct measurement, but it is the standard method when you do not have supplier data. As you mature, you can ask suppliers for their actual emissions.

Does renewable energy I buy reduce my Scope 2 emissions to zero?

Purchasing renewable energy credits or signing a power purchase agreement reduces your reported Scope 2, but the grid still burns fossil fuels to power your building. The credits represent the environmental benefit of renewable generation elsewhere. This is valid under most standards, but it is different from actually using zero-carbon electricity.

Why is my Scope 3 so much larger than my Scopes 1 and 2?

For most companies, Scope 3 is larger because it includes your entire supply chain and customer use. A clothing retailer's Scope 3 includes farming, manufacturing, shipping, and washing by millions of customers — far more than the emissions from running stores. This is normal and expected.

Can I reduce my Scope 3 emissions if I do not own the companies in my supply chain?

Yes, but it requires collaboration. You can set supplier standards, offer incentives for lower-emission practices, switch to suppliers with better emissions profiles, or redesign products to use less material or energy. You cannot control your suppliers' emissions directly, but you can influence them through purchasing decisions and partnerships.