Jump to: Why you need this on your desk · The three scopes explained · The 15 Scope 3 categories · GWP & the core formula · Where to find emission factors · Common mistakes · FAQ
Why This Cheat Sheet Belongs Open on Your Second Monitor
Anyone doing carbon accounting hits the same wall repeatedly: is business travel Scope 3 category 6 or 7? Does Scope 2 need one number or two? What GWP value does methane actually carry? The answers are all in the GHG Protocol’s official standards — spread across several long PDFs that nobody re-reads every time a question comes up.
This cheat sheet compresses the parts you look up most often into two printable pages: the three scopes defined side by side, all 15 Scope 3 categories with a one-line description each, the Scope 2 dual-reporting requirement, the core emissions formula, a GWP reference table for the main gases, and where to actually find emission factors. No fluff, no 40-page PDF — just the reference table you keep open while building a footprint.
📋 What it is: A free, 2-page, print-ready PDF summarizing the GHG Protocol Corporate Standard’s scope definitions, the full Scope 3 category list, GWP-100 values, the core calculation formula, and emission factor sources — the quick-reference companion to the full GHG Protocol documents, not a replacement for them.
The Three Scopes, Side by Side
The GHG Protocol Corporate Standard classifies a company’s emissions into three scopes based on where they occur relative to its operations and how much control the company has over them.
| Scope | Definition | Control | Example |
|---|---|---|---|
| Scope 1 | Direct emissions from owned/controlled sources | Full operational control | Company boilers, owned vehicle fleet |
| Scope 2 | Indirect emissions from purchased energy | Full control via energy choice | Purchased electricity, steam, heating |
| Scope 3 | All other value-chain emissions | Limited or no direct control | Purchased goods, business travel |
Scope 1 splits into four categories every cheat sheet should list clearly: stationary combustion (boilers, furnaces, generators), mobile combustion (owned vehicles, forklifts, aircraft), fugitive emissions (refrigerant leaks, SF6 from switchgear), and process emissions (chemical reactions in manufacturing).
Scope 2 has a requirement that trips up more companies than any other single rule in the standard: you must report both a location-based figure (using the local grid’s average emission factor) and a market-based figure (using contractual instruments like RECs, PPAs, or supplier-specific rates) — not just whichever number looks better.
⚠️ The rule everyone forgets: Scope 2 dual reporting is not optional. The GHG Protocol Scope 2 Guidance requires both location-based and market-based figures side by side. Reporting only one is one of the most common — and most easily avoided — compliance gaps.
The 15 Scope 3 Categories — Memorize the Split, Not the Numbers
Scope 3 is where most carbon accounting effort (and most confusion) concentrates. The trick to remembering the 15 categories isn’t memorizing the numbers — it’s remembering the split: categories 1–8 are upstream (emissions from producing what you buy) and categories 9–15 are downstream (emissions from what happens after you sell).
| # | Upstream category |
|---|---|
| 1 | Purchased goods & services |
| 2 | Capital goods |
| 3 | Fuel- & energy-related activities |
| 4 | Upstream transportation & distribution |
| 5 | Waste generated in operations |
| 6 | Business travel |
| 7 | Employee commuting |
| 8 | Upstream leased assets |
| # | Downstream category |
|---|---|
| 9 | Downstream transportation & distribution |
| 10 | Processing of sold products |
| 11 | Use of sold products |
| 12 | End-of-life treatment of sold products |
| 13 | Downstream leased assets |
| 14 | Franchises |
| 15 | Investments |
For most companies with physical products, category 11 (use of sold products) is the single largest Scope 3 category — think of a car manufacturer’s tailpipe emissions over the vehicle’s lifetime, or a software company’s data-center electricity draw from customer use. For financial institutions, category 15 (investments) — the GHG Protocol’s “financed emissions” — is typically the dominant category by an enormous margin.
GWP Values and the Core Calculation
Every emissions calculation reduces to one formula:
Emissions (tCO2e) = Activity Data × Emission Factor × GWP (if the factor isn’t already expressed in CO2 equivalent)
The GWP (Global Warming Potential) step converts non-CO2 gases into a CO2-equivalent basis so they can be added together into one total. The values below are commonly cited GWP-100 figures as referenced by the GHG Protocol — always confirm and disclose which IPCC Assessment Report vintage (AR4, AR5 or AR6) you’re using, since the values shift slightly between reports.
| Gas | GWP-100 (approx.) |
|---|---|
| CO2 (carbon dioxide) | 1 (reference gas) |
| CH4 (methane) | ≈ 28–30 |
| N2O (nitrous oxide) | ≈ 265–273 |
| SF6 (sulphur hexafluoride) | ≈ 23,500 |
| NF3 (nitrogen trifluoride) | ≈ 17,200 |
| HFCs (hydrofluorocarbons) | 100s – 14,000+ (varies by compound) |
✅ Consistency matters more than precision: Switching GWP vintages between reporting years without disclosure is a common audit finding. Pick one IPCC Assessment Report’s GWP-100 values, state which one you used, and keep it consistent year over year — even a slightly “older” dataset applied consistently is more defensible than switching silently.
Where to Actually Find Emission Factors
Knowing the formula doesn’t help without a reliable emission factor. These are the sources practitioners return to most:
| Source | What it provides |
|---|---|
| EPA (US) | GHG Emission Factors Hub — US-specific factors for fuel, electricity, transport |
| DEFRA (UK) | UK Government GHG Conversion Factors, updated annually |
| IEA | Grid electricity emission factors by country — essential for location-based Scope 2 |
| Ecoinvent / national LCA databases | Life-cycle factors for purchased goods — the backbone of Scope 3 category 1 |
| Supplier-specific data | The most accurate source available for Scope 3 — always preferable to a generic factor when obtainable |
Four Mistakes This Cheat Sheet Helps You Avoid
- Reporting only one Scope 2 method. Location-based and market-based are both required, not a choice.
- Double-counting across companies. One company’s Scope 1 (its own fleet) is another company’s Scope 3 category 4 or 9 (transportation) — make sure your boundary is clear.
- Mixing GWP vintages. Switching between AR4, AR5 and AR6 GWP values inconsistently year to year distorts trend reporting.
- Omitting biogenic CO2. The GHG Protocol requires biogenic CO2 to be disclosed separately from the Scope totals, not folded in or left out entirely.
💡 The bottom line: Scope 1 and 2 are usually the smallest share of a company’s footprint and the easiest to measure. Scope 3 is typically 70–90% of total emissions for most sectors — and the hardest to get right. Print this cheat sheet, keep it next to your calculation workbook, and start with the Scope 3 categories most relevant to your business model.
Related Resources & Tools
- Carbon Footprint Calculator (Scope 1, 2 & 3) — put these definitions into a working spreadsheet
- CSRD Double Materiality Matrix Template — where your Scope 1/2/3 data feeds into ESRS E1 disclosure
- Supplier ESG Assessment Questionnaire — collect the supplier-specific data this cheat sheet recommends for Scope 3
- Watershed — automated carbon accounting software covering all three scopes
- Persefoni — carbon accounting with financed-emissions (category 15) depth
- AI Carbon Accounting 2026 — how AI platforms are automating Scope 1/2/3 calculation
Provided free by AiGreenTools for educational and reference use. It summarizes the GHG Protocol Corporate Standard and Scope 2 Guidance but is not a substitute for the official GHG Protocol documents — always consult the primary standards for a compliance-critical determination.
