What are Scope 1, 2 and 3 in plain English?

Scope 1 is fuel you burn yourself (vehicles, generators, gas cookers) plus refrigerant leaks. Scope 2 is the electricity you buy. Scope 3 is everything else — what you purchase, how goods move, how staff travel and commute, and what happens to your waste.

Do I need all 15 Scope 3 categories?

Almost never for a first report. The GHG Protocol defines 15 categories, but for a typical company, nonprofit, school or public agency, four or five dominate: purchased goods and services, freight, business travel, employee commuting, and waste. Start there and expand only if a customer, funder or regulator questionnaire asks for more.

Is a company car Scope 1 or Scope 3?

If the organization owns or leases and operates the vehicle, the fuel is Scope 1. If an employee drives their own car and claims mileage, or you use a courier, that travel or freight sits in Scope 3. The test is control: whose asset burned the fuel?

Which frameworks ask for these numbers?

The GHG Protocol is the accounting standard behind all of them — it defines the scopes and how to add them up. On top of that, ISSB's IFRS S2 is the climate-disclosure standard increasingly written into listing rules, GRI 305 is the sustainability-reporting standard many stakeholders still ask for, and CDP is a widely used investor and customer questionnaire. If you're a Singapore-listed issuer, SGX layers IFRS S2 on top of that base — see our SGX deadlines guide for the timeline.

Guide

Scope 1, 2 and 3, explained in 10 minutes

The GHG Protocol scopes translated into the documents already sitting in your accounts folder: which bill proves which scope, and which Scope 3 categories actually matter for a typical organization.

Last updated July 2026

The scopes are a filing system, not a science project

The GHG Protocol's three scopes sound abstract until you realise they map almost one-to-one onto documents any organization already keeps for accounting. The whole exercise is answering one question three times: whose fuel got burned, and where?

Scope 1 — you burned it. Diesel in the delivery van, gas under the kitchen hob, petrol in the site vehicle, and refrigerant that leaked out of the aircon or cold room. Evidence: fuel receipts, gas bills, aircon servicing invoices.
Scope 2 — the power station burned it for you. Every kWh on your electricity bill was generated somewhere, and a national or regional grid-average factor tells you how much CO₂ each kWh carried. Evidence: your electricity bill.
Scope 3 — someone else burned it because of you. Your suppliers making what you buy, the ship carrying your stock, the flight to a conference, staff commuting, and the truck taking your waste away. Evidence: supplier invoices, freight invoices, itineraries, waste-disposal invoices.

That is the entire concept. The rest of this guide is turning your accounts-payable folder into those three piles — and it works the same way whether the letterhead says company, nonprofit, school, or public agency.

Which document proves which scope

This table is the one to keep. Work through a year of paperwork and sort each document into a row:

| Document in your accounts folder | Scope | What to extract | Typical factor | | --- | --- | --- | --- | | Petrol / diesel receipts, fleet-card statements | 1 | Litres by fuel type | Diesel 2.686, petrol 2.3153 kgCO₂e/litre (DEFRA 2025) | | Natural gas / town gas bill | 1 | kWh of gas | 0.18293 kgCO₂e/kWh (DEFRA 2025) | | LPG cylinder invoices | 1 | Litres | 1.5594 kgCO₂e/litre (DEFRA 2025) | | Aircon / refrigeration servicing invoice showing gas top-up | 1 | kg of refrigerant, by type | Varies by refrigerant | | Electricity bill (utility or retailer) | 2 | kWh | Grid-average factor for your country (region-specific — e.g. Singapore 0.4020 kgCO₂e/kWh, EMA 2024 data year) | | Supplier invoices for goods and services | 3 (purchased goods) | Spend or quantities | Spend- or activity-based | | Freight / courier / forwarder invoices | 3 (freight) | Tonne-km by mode | Road 0.1153, sea 0.0116, air 0.6022 kgCO₂e/t-km (DEFRA 2025) | | Flight itineraries, hotel folios | 3 (business travel) | Passenger-km; room-nights | Long-haul 0.19085 kgCO₂e/pax-km; hotel factor is region-specific (e.g. Singapore 22.5 kg/room-night) | | Staff addresses / transport survey | 3 (commuting) | Distance by mode | Mode-specific | | Waste-disposal / recycling invoices | 3 (waste) | Tonnes by treatment | Treatment-specific |

One note on the factors: for fuels and freight we default to the UK DEFRA/DESNZ 2025 conversion factors, the most widely used open-licence set internationally. Electricity grid factors, by contrast, are country- or region-specific — see the "If you're in Singapore" section below for the EMA figures if that is your grid. Every calculation on tc02e.com shows the exact factor, source and licence next to the result.

Scope 3: fifteen categories, four or five that matter

The GHG Protocol defines 15 Scope 3 categories, and the list intimidates people into doing nothing. For a typical organization — a trading firm, light manufacturer, F&B operator, professional-services practice, school, clinic, or nonprofit running a single site — most categories are zero or negligible. Concentrate on:

Purchased goods and services — usually the biggest single number. First pass: estimate from spend; refine your top suppliers later.
Upstream freight — forwarder invoices give you tonnes and routes. Note the spread: sea freight is 0.0116 kgCO₂e per tonne-km, air freight is 0.6022 — roughly fifty times higher per tonne-km.
Business travel — flights dominate; itineraries give you the routes.
Employee commuting — a simple staff survey once a year is enough.
Waste — disposal invoices, usually small but easy to include.

Categories like franchises, investments, or downstream leased assets exist for larger, more complex organizations; if none of your paperwork mentions them, skip them and say so in your methodology note.

A worked example: a 12-person trading firm

One year of documents, sorted by the table above:

Scope 1: two delivery vans used 4,200 litres of diesel. 4,200 × 2.686 = 11,281 kgCO₂e ≈ 11.3 tonnes.
Scope 2: office and small warehouse used 38,000 kWh. Using a sample grid factor of 0.4020 kgCO₂e/kWh (substitute your own grid's published factor): 38,000 × 0.4020 = 15,276 kgCO₂e ≈ 15.3 tonnes.
Scope 3, freight: 120 tonnes of goods shipped 8,000 km by sea: 120 × 8,000 × 0.0116 = 11,136 kgCO₂e ≈ 11.1 tonnes. One urgent 2-tonne air shipment over 3,300 km adds 2 × 3,300 × 0.6022 = 3,975 kgCO₂e ≈ 4.0 tonnes — a third of the sea total for under 2% of the cargo.
Scope 3, travel: two return long-haul trips, about 42,000 passenger-km total: 42,000 × 0.19085 = 8,016 kgCO₂e ≈ 8.0 tonnes, plus six hotel nights at a sample factor of 22.5 kg/room-night = 135 kgCO₂e.

Running total: roughly 50 tonnes CO₂e, with measured Scope 3 already nearly half — before purchased goods, which would likely dominate once estimated. You can reproduce each line with our fleet fuel calculator, business electricity calculator and freight calculator, or upload the bills and let the extraction do the sorting.

What this approach doesn't cover

Honesty about limits keeps the numbers defensible:

Spend-based Scope 3 is an estimate, not a measurement. It flags hotspots; it will not survive a supplier-specific audit question without refinement.
Refrigerants need servicing records. If your aircon contractor never writes down top-up quantities, your Scope 1 has a gap — ask for it on the next invoice.
Regional grid factors vary. If you have operations in more than one country, the local factor matters: Malaysia is approximately 0.61 kgCO₂e/kWh, Indonesia approximately 0.69, the UK 0.207 (Ember and DEFRA respectively) — one country's grid factor does not transfer to another.
This is a disclosure baseline, not assurance. Our output shows its working — factor, source, licence — but it is not a substitute for external assurance, which phases in on later timelines under most frameworks.

Why this matters, whatever kind of organization you are

Reporting requests do not arrive only for large listed companies anymore. Funders, customers, banks, boards, and regulators all ask some version of the same question — "what are your emissions?" — and the arithmetic behind the answer is identical whether you are a company, a nonprofit, a school, or a public agency. The GHG Protocol scopes above feed directly into IFRS S2, GRI 305, CDP and most national disclosure codes; none of them invent a different accounting method, they just ask for the same three piles in a particular format. Starting with the free tier here — three uploads a day anonymously, ten with an email, files deleted after 30 days — costs you an afternoon and gives you a defensible baseline before anyone asks.

If you're in Singapore

Singapore's climate-reporting regime adds specifics worth knowing on top of the universal method above. The grid emission factor comes from EMA's Singapore Energy Statistics: 0.4085 kgCO₂e/kWh for the 2023 data year (SES 2024), updated to 0.4020 for the 2024 data year (SES 2025) — use the year matching your bills, and see our Singapore grid emission factor guide for the full explanation.

On the reporting side, no rule names non-listed SMEs directly — the mandate for large non-listed companies (≥ S$1 billion revenue) is deferred to around FY2030. But the SGX timeline pulls suppliers in sideways: all SGX-listed issuers report Scope 1 and 2 from FY2025, and Straits Times Index constituents add Scope 3 from FY2026. Their Scope 3 is their suppliers' Scope 1 and 2, so questionnaires are already flowing down supply chains. Boards of listed customers carry personal responsibility under listing rules 711A/711B, which makes them persistent askers. If reporting costs worry you, a dedicated SME sustainability-reporting programme covers 50% of costs through October 2027 (the separate EnterpriseSG SRG covers 30%, capped at S$150,000, for listed or ≥ S$100M-revenue companies). See our SGX deadlines guide for the full timeline.

Sources

GHG Protocol — Corporate Standard and Scope 3 Standard: ghgprotocol.org
EMA — Singapore Energy Statistics (grid emission factor): ema.gov.sg
UK DESNZ/DEFRA — greenhouse gas conversion factors 2025: gov.uk
SGX RegCo — sustainability reporting requirements: sgx.com/regulation
Ember — Yearly Electricity Data (country grid factors): ember-energy.org
US EPA — eGRID (US grid factor): epa.gov/egrid

Frequently asked questions

What are Scope 1, 2 and 3 in plain English?: Scope 1 is fuel you burn yourself (vehicles, generators, gas cookers) plus refrigerant leaks. Scope 2 is the electricity you buy. Scope 3 is everything else — what you purchase, how goods move, how staff travel and commute, and what happens to your waste.
Do I need all 15 Scope 3 categories?: Almost never for a first report. The GHG Protocol defines 15 categories, but for a typical company, nonprofit, school or public agency, four or five dominate: purchased goods and services, freight, business travel, employee commuting, and waste. Start there and expand only if a customer, funder or regulator questionnaire asks for more.
Which document proves which scope?: Fuel receipts and gas bills prove Scope 1; your electricity bill proves Scope 2; supplier invoices, freight invoices, flight itineraries and waste-disposal invoices cover the main Scope 3 categories. If it is in your accounts-payable folder, it maps to a scope.
Is a company car Scope 1 or Scope 3?: If the organization owns or leases and operates the vehicle, the fuel is Scope 1. If an employee drives their own car and claims mileage, or you use a courier, that travel or freight sits in Scope 3. The test is control: whose asset burned the fuel?
Which frameworks ask for these numbers?: The GHG Protocol is the accounting standard behind all of them — it defines the scopes and how to add them up. On top of that, ISSB's IFRS S2 is the climate-disclosure standard increasingly written into listing rules, GRI 305 is the sustainability-reporting standard many stakeholders still ask for, and CDP is a widely used investor and customer questionnaire. If you're a Singapore-listed issuer, SGX layers IFRS S2 on top of that base — see our SGX deadlines guide for the timeline.