Turn your Bill of Materials into a Scope 3 inventory.
Get a fast estimate using DESNZ 2025 government factors — or use real supplier EPD data for greater accuracy. Add sources by category, see your biggest hotspots, export a GHG Protocol disclosure summary.
What you get: total tCO₂e broken down by category · identify your biggest hotspot · GHG Protocol disclosure text ready to copy · CSV export. Use government averages or paste in your own EPD data for any line item.
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Add emissions by category
📦 Category 1 — Purchased goods & services Activity-based✦ Use real EPD data for precision
All upstream emissions from materials and goods you purchase. Factors are from DESNZ 2025 primary material production (kg CO₂e per tonne). Use EPD A1–A3 values for greater accuracy — override the factor field with your EPD value.
DESNZ 2025 material factors (auto-filled) are average UK production figures covering all upstream emissions per tonne. Source: UK Government DESNZ 2025 "Material use" sheet, Open Government Licence.
EPD A1–A3 factors are product-specific values from a verified Environmental Product Declaration. More accurate. Enter them by overriding the factor field — make sure units match (if your EPD is per kg, either convert to tonnes or change the quantity accordingly).
Accuracy note: DESNZ material factors can be ±50% from specific products. The 2022 DESNZ update changed the concrete/cement factor by +119% due to a methodology revision. Always check which factor year you're using when tracking trends year-on-year.
Auto-filled — edit to use EPD A1–A3 GWP-total value
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kg CO₂e
= tCO₂e
🏗 Category 2 — Capital goods Activity-based
Upstream emissions from purchased capital goods: machinery, equipment, vehicles, buildings, IT hardware. Report all emissions in the year of acquisition — GHG Protocol does not spread them over asset life.
⚠ No dedicated DESNZ Cat 2 factors exist. This tool uses material proxies from the DESNZ 2025 Material use sheet — e.g. metal machinery uses the Metals factor (3,824 kg CO₂e/t), IT equipment uses the Electrical items-IT factor (24,865 kg CO₂e/t). These are indicative only. For formal Cat 2 reporting, use supplier-specific lifecycle data or a verified EPD where available.
Capital goods (Cat 2) are assets with useful life >1 year used in your operations: manufacturing machinery, computers, company vehicles, cranes, office fit-out. Purchased goods (Cat 1) are consumables: raw materials, components, packaging, maintenance supplies.
For equipment, use the relevant material factor as a proxy — e.g. a steel machine → metals factor. For precision, ask the supplier for an EPD or lifecycle assessment. Electronics have very high factors (24,865 kg CO₂e/t for IT equipment per DESNZ 2025).
kg CO₂e per unit
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kg CO₂e
= tCO₂e
⚡ Category 3 — Fuel & energy activities Activity-based
Upstream (well-to-tank) emissions from producing the fuels and electricity you consume. This is separate from and additional to your Scope 1 (combustion) and Scope 2 (purchased electricity) emissions.
Your Scope 1 covers the combustion of fuel (e.g. diesel burning = 2.57 kg CO₂e/litre). But extracting, refining and transporting that diesel to you also emits carbon — that's the well-to-tank (WTT) factor (~0.58 kg CO₂e/litre for diesel). WTT goes in Cat 3.
Similarly, the UK grid loses ~7.5% of electricity in transmission — those losses (T&D, 0.020 kg CO₂e/kWh) and the upstream emissions from generating electricity (WTT, 0.029 kg CO₂e/kWh) are also Cat 3.
Source: DESNZ 2025 WTT-fuels and Transmission and distribution sheets.
Homeworking: DESNZ 2025 provides a homeworking factor of 0.334 kg CO₂e per FTE working hour (office equipment + heating). Multiply by number of employees × average homeworking hours per year. This is a Scope 3 Category 3 item — the upstream energy used in employees' homes.
kg CO₂e per unit — WTT/upstream only
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kg CO₂e
= tCO₂e
🚛 Category 4 — Upstream transport Activity-based
Emissions from transporting purchased goods to your facilities. Enter weight, distance, and vehicle type — the tonne-km calculation is automatic.
Tonne-km = weight of goods (tonnes) × distance travelled (km).
Example: 20 tonnes of steel delivered 150 km = 3,000 tonne-km × 0.211 kg CO₂e/t·km = 633 kg CO₂e.
Typical distances: Local UK delivery ~50 km · National UK ~300 km · European road ~1,500 km · Sea freight ~10,000–20,000 km.
Vehicle choice: Most heavy construction deliveries = HGV rigid >17t (0.211 kg/t·km). General HGV average = 0.122. Sea bulk = 0.00353. Air freight is ~50× more carbon-intensive than sea.
Source: DESNZ 2025 Freighting goods sheet.
kg CO₂e per tonne·km
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kg CO₂e
= tCO₂e
🗑 Category 5 — Waste in operations Activity-based
Emissions from treating waste generated by your operations. The emissions occur at the waste facility — these are Scope 3, not Scope 1. Note: wood sent to landfill has an extremely high factor (925 kg CO₂e/t) due to methane from decomposition.
Recycling / closed-loop (1.01 kg CO₂e/t): Best option for inert construction materials. Only transport emissions. Landfill: Very low for inert materials (1.26 kg CO₂e/t), but extremely high for organic materials — wood (925 kg/t), plasterboard (72 kg/t) due to methane generation. Incineration with energy recovery: ~4.69 kg CO₂e/t for most materials — better than landfill for organic waste but worse than recycling.
If you don't know the split, use "Average construction — landfill" as a conservative estimate.
Source: DESNZ 2025 Waste disposal sheet.
kg CO₂e per tonne
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kg CO₂e
= tCO₂e
✈ Category 6 — Business travel Activity-based
Emissions from employee travel in vehicles not owned by your company. Flight factors include radiative forcing (RF) — the additional warming effect of contrails at altitude, which roughly doubles the climate impact of flying.
Radiative forcing (RF) accounts for the fact that aircraft contrails and high-altitude emissions warm the climate beyond just their CO₂. The IPCC estimates RF roughly doubles the effective warming of flights. The GHG Protocol and DESNZ recommend including RF for completeness — these factors do.
Some organisations report with and without RF side-by-side. If you need both, enter the flight without RF factor from the DESNZ sheet and note it separately.
Example distances: London–Edinburgh 630 km · London–Amsterdam 370 km · London–New York 5,540 km · London–Sydney 17,000 km.
Source: DESNZ 2025 Business travel-air and Business travel-land sheets (incl. RF).