Organization footprint calculator (Scope 1, 2 and 3 screening)

What a screening footprint is

A screening footprint is a fast, honest first estimate of an organization's greenhouse gas emissions, built from the handful of activities that usually account for most of the total: energy, fuel, refrigerant, travel, commuting, waste and water. It is not a substitute for a full inventory — it won't catch every purchased good, every subcontractor, or every embodied emission in a piece of equipment — but it answers the question that shows up first, whether that question comes from a funder, a board member, a customer's supplier questionnaire, or your own curiosity: roughly how big is this?

This calculator covers ten activities across all three GHG Protocol scopes on a single page, because that is the shape the question usually arrives in. Under the surface, every field keeps its correct scope and category tag, and the results view breaks the total back out so you can see where the mass actually sits — often a surprise, since electricity and flights dominate more often than intuition suggests.

The arithmetic is identical whether you run a company, a nonprofit, a school, or a public agency: emissions = activity quantity × emission factor, summed across everything you measure. What differs between organization types is which categories are material — a school's largest line is usually electricity and transport, a manufacturer's is usually fuel and refrigerant, a services firm's is usually flights and commuting. This calculator gives you all ten so you can see your own shape.

Scope 1 — what you burn directly

Scope 1 covers emissions from sources you own or control: fuel burned in your own boilers, generators, or vehicles, and refrigerant that leaks from equipment you operate.

Diesel and petrol come from fuel-card statements or pump receipts — litres burned, multiplied by a combustion factor. Refrigerant is trickier to observe directly, so the field uses the kilograms of gas refilled at your last aircon or refrigeration service as a proxy for what leaked out over the period; the invoice is the document. Natural gas burned in boilers or process heat is also Scope 1, and shares a field with the Scope 2 electricity number below because both come off utility bills.

If your organization has no fleet, no boiler, and no refrigeration plant — a small office or a fully outsourced operation, for instance — Scope 1 can legitimately be close to zero. That is a real result, not a missing one.

Scope 2 — the electricity and heat you buy

Scope 2 is purchased electricity (and, less commonly, purchased heat or steam) — indirect emissions from generation you pay for but don't own. For almost every organization type, from a school to a warehouse to a clinic, this is the largest or second-largest line, which is why it sits first on this form. The electricity factor is country-specific: pick your region above and the calculator applies the matching grid intensity, sourced from national regulators where they publish one and from Ember's generation data otherwise.

Scope 3 — everything else that's still yours to count

Scope 3 is indirect emissions up and down your value chain, and it is where most organizations' footprints actually live once travel and waste are counted. This calculator covers four Scope 3 categories that are usually both material and measurable without a formal supply-chain exercise:

• Business flights (category 6) — passenger-kilometres for long-haul trips, the single biggest per-trip emitter in most travel programmes.
• Hotel nights (category 6) — room-nights booked for business travel, using a country-specific factor tied to the region selector.
• Staff car commuting (category 7) — total annual kilometres driven to work, using a fuel-unknown average factor as a starting estimate.
• Waste to landfill (category 5) — tonnes of mixed commercial waste, which carries a much higher factor than recycling or composting because landfill decomposition releases methane.

Water appears here too, split between supply (commonly category 1, purchased goods and services) and treatment (commonly category 5, waste generated in operations) — this calculator asks only for the supply side; the water usage calculator covers both halves with the treatment factor included.

A worked example

A 40-person nonprofit office, for one year: 12,000 kWh electricity (Singapore grid, 0.4020 kgCO₂e/kWh), 3,000 kWh gas (0.18293 kgCO₂e/kWh), no fleet vehicles, 2 kg R-410A refilled during an aircon service (1924 kgCO₂e/kg), 15,000 pax-km of long-haul flights (0.19085 kgCO₂e/pax-km), 20 room-nights (Singapore factor 22.5 kgCO₂e/night), 50,000 km of staff commuting (0.16725 kgCO₂e/km), 5 tonnes of mixed waste to landfill (520.5327 kgCO₂e/tonne), and 300 m³ of water supplied (0.1913 kgCO₂e/m³).

Electricity: 12,000 × 0.4020 = 4,824 kgCO₂e

Gas: 3,000 × 0.18293 = 548.8 kgCO₂e

Refrigerant: 2 × 1924 = 3,848 kgCO₂e

Flights: 15,000 × 0.19085 = 2,862.8 kgCO₂e

Hotels: 20 × 22.5 = 450 kgCO₂e

Commuting: 50,000 × 0.16725 = 8,362.5 kgCO₂e

Waste: 5 × 520.5327 = 2,602.7 kgCO₂e

Water: 300 × 0.1913 = 57.4 kgCO₂e

Total ≈ 23,556 kgCO₂e ≈ 23.6 tCO₂e

Commuting turns out to be a bigger line than the electricity bill in this example — exactly the kind of thing a screening footprint is for. Nobody guesses that a single aircon service tops the flights bill until they run the numbers.

What this calculator doesn't cover

• Purchased goods and services. Spend on equipment, materials, and contracted services is Scope 3 category 1/2 and needs a spend-based method — see the purchased goods & services calculator.
• Freight and shipping. Inbound and outbound logistics run on a tonne-kilometre method, not covered by these ten fields — use the freight calculator.
• Waste beyond mixed landfill. Food waste, paper, and alternative disposal routes (composting, recycling, incineration with energy recovery) each carry very different factors — see the waste disposal calculator for the full six-stream breakdown.
• Other refrigerant gases. This form only takes R-410A. If your organization runs R-32, R-134a, R-404A, R-407C, or SF6 equipment, use the refrigerant & air-con leaks calculator.
• Water treatment. Only mains supply is counted here; wastewater treatment has its own factor — see the water usage calculator.
• Short-haul flights, IT equipment, and market-based Scope 2. All real categories, none captured by this ten-field screening pass.

None of these gaps make the total wrong; they define what it screens and what it doesn't. For a fuller picture, the deep-dive calculators above cover more ground, each with the same factor-and-source transparency.

Where this fits in your reporting

This one calculator touches all three GHG Protocol scopes at once — electricity is Scope 2, fuel and refrigerant are Scope 1, and flights, hotels, commuting, waste and water sit in various Scope 3 categories (6, 7, 5, and 1 respectively). Whichever framework asks for the number next — ISSB IFRS S2, GRI 305, a CDP questionnaire, or a national reporting code — the underlying arithmetic doesn't change with the organization type filing it: a company, a nonprofit, a school, and a public agency all sum activity quantity times emission factor the same way. Singapore-listed issuers have their own deadlines for when Scope 1/2 and Scope 3 become mandatory — see the SGX climate reporting deadlines guide if that applies to you. When you'd rather not type ten numbers in by hand, upload your bills and invoices directly and let the same factors apply automatically.

Sources

• GHG Protocol, Corporate Accounting and Reporting Standard — Scope 1/2/3 definitions and category boundaries: ghgprotocol.org/corporate-standard
• UK Government (DESNZ/DEFRA), Greenhouse gas reporting: conversion factors 2025 — fuel, refrigerant, waste, water, and commuting factors (Open Government Licence v3.0): gov.uk/government/collections/government-conversion-factors-for-company-reporting
• EPA GHG Emission Factors Hub, 2025 — refrigerant GWP values (public domain): epa.gov/climateleadership/ghg-emission-factors-hub
• Ember, Yearly Electricity Data — country generation intensities (CC-BY): ember-energy.org/data/yearly-electricity-data
• Energy Market Authority, Singapore Energy Statistics — Singapore grid emission factor: ema.gov.sg/resources/singapore-energy-statistics