RVBA-AONConsulting →
Aon — carbon factors
Reference emission factors relevant to the Consulting sector, curated from authoritative published sources. Use these to estimate spend-based or activity-based emissions where the firm's own disclosures don't cover a category, or to spot-check disclosed figures against the consensus range.
The spread shown for each factor is the range across published sources for the sector — not Aon's own values. A wide spread means the published sources disagree (use with caution); a tight spread is a well-established consensus. Aon's own disclosed figures live on the Ratios tab. (Plotting where Aon sits within each distribution is on the roadmap.)
Factors curated
67
Sources
4
Categories
33
Latest vintage
2024
Sources (4) · Geographies: GLOBAL, GB, AE, DE, FR, IN, JP, US, EU, NO, PT, AT, CA, DK, CH, NL, IT
DESNZ Greenhouse gas reporting: conversion factors2024 v1.1 (Oct 2024 reissue)activity based· Open Government Licence v3.0
DEFRA UK consumption-based spend factors by SIC2022 footprint (published April 2025)spend based· Open Government Licence v3.0
USEEIO / EPA Supply Chain GHG Emission Factorsv1.3.0 (USEEIOv2.2.22-GHG, BEA 2017 Detail, 2022 inventory)spend based· Public Domain (US Government work)
EXIOBASE 3.8.2 (MRIO consumption-based)3.8.2 (2021 release, 2019 base year)spend based· CC-BY-SA 4.0
Spend-based (per currency unit) 6 categories · 40 factors
Multiply spend (in the stated currency, in the stated reference year) by the factor to estimate kgCO2e for that category of procurement. Spend-based factors carry material uncertainty but are useful when you have no activity data.
Accounting and tax services
| Value | Unit | Geo | Year | Scope | Source | Notes |
|---|---|---|---|---|---|---|
| 0.0690 | kgCO2e/GBP | GB | 2022 | Cradle → gate S1 · S2 loc · S3↑ | defra_sic_2022 purchaser · GBP 2022 | SIC 69.2. DEFRA consumption-based (UK MRIO) — captures imports unlike USEEIO production-based. |
| 0.0873 | kgCO2e/USD | GB | 2022 | Cradle → gate S1 · S2 loc · S3↑ | defra_sic_2022 purchaser · USD 2022 | SIC 69.2. Native unit is GBP — converted to USD via static FX 0.79 GBP/USD for cross-source comparison. Recompute with accounting-period FX for production calculations. |
| 0.0540 | kgCO2e/USD | US | 2022 | Cradle → gate S1 · S2 loc · S3↑ | useeio_v1_3 purchaser · USD 2022 | USEEIO commodity 541200. NAICS 541211. Purchaser price (with margins). Multiply 2022 USD spend × value to get kgCO2e. |
| 0.0427 | kgCO2e/GBP | US | 2022 | Cradle → gate S1 · S2 loc · S3↑ | useeio_v1_3 purchaser · GBP 2022 | USEEIO commodity 541200, converted USD→GBP at static rate (0.79). For production, recompute with the accounting-period FX rate. |
Engineering services
| Value | Unit | Geo | Year | Scope | Source | Notes |
|---|---|---|---|---|---|---|
| 0.2405 | kgCO2e/USD | GB | 2022 | Cradle → gate S1 · S2 loc · S3↑ | defra_sic_2022 purchaser · USD 2022 | SIC 71. Native unit is GBP — converted to USD via static FX 0.79 GBP/USD for cross-source comparison. Recompute with accounting-period FX for production calculations. |
| 0.1900 | kgCO2e/GBP | GB | 2022 | Cradle → gate S1 · S2 loc · S3↑ | defra_sic_2022 purchaser · GBP 2022 | SIC 71. DEFRA consumption-based (UK MRIO) — captures imports unlike USEEIO production-based. |
| 0.0814 | kgCO2e/GBP | US | 2022 | Cradle → gate S1 · S2 loc · S3↑ | useeio_v1_3 purchaser · GBP 2022 | USEEIO commodity 541300, converted USD→GBP at static rate (0.79). For production, recompute with the accounting-period FX rate. |
| 0.1030 | kgCO2e/USD | US | 2022 | Cradle → gate S1 · S2 loc · S3↑ | useeio_v1_3 purchaser · USD 2022 | USEEIO commodity 541300. NAICS 541330. Purchaser price (with margins). Multiply 2022 USD spend × value to get kgCO2e. |
Environmental consulting services
| Value | Unit | Geo | Year | Scope | Source | Notes |
|---|---|---|---|---|---|---|
| 0.0900 | kgCO2e/USD | US | 2022 | Cradle → gate S1 · S2 loc · S3↑ | useeio_v1_3 purchaser · USD 2022 | USEEIO commodity 5416A0. NAICS 541620. Purchaser price (with margins). Multiply 2022 USD spend × value to get kgCO2e. |
| 0.0711 | kgCO2e/GBP | US | 2022 | Cradle → gate S1 · S2 loc · S3↑ | useeio_v1_3 purchaser · GBP 2022 | USEEIO commodity 5416A0, converted USD→GBP at static rate (0.79). For production, recompute with the accounting-period FX rate. |
Legal services
| Value | Unit | Geo | Year | Scope | Source | Notes |
|---|---|---|---|---|---|---|
| 0.0520 | kgCO2e/GBP | GB | 2022 | Cradle → gate S1 · S2 loc · S3↑ | defra_sic_2022 purchaser · GBP 2022 | SIC 69.1. DEFRA consumption-based (UK MRIO) — captures imports unlike USEEIO production-based. |
| 0.0658 | kgCO2e/USD | GB | 2022 | Cradle → gate S1 · S2 loc · S3↑ | defra_sic_2022 purchaser · USD 2022 | SIC 69.1. Native unit is GBP — converted to USD via static FX 0.79 GBP/USD for cross-source comparison. Recompute with accounting-period FX for production calculations. |
| 0.0324 | kgCO2e/GBP | US | 2022 | Cradle → gate S1 · S2 loc · S3↑ | useeio_v1_3 purchaser · GBP 2022 | USEEIO commodity 541100, converted USD→GBP at static rate (0.79). For production, recompute with the accounting-period FX rate. |
| 0.0410 | kgCO2e/USD | US | 2022 | Cradle → gate S1 · S2 loc · S3↑ | useeio_v1_3 purchaser · USD 2022 | USEEIO commodity 541100. NAICS 541110. Purchaser price (with margins). Multiply 2022 USD spend × value to get kgCO2e. |
Management consulting services
| Value | Unit | Geo | Year | Scope | Source | Notes |
|---|---|---|---|---|---|---|
| 0.1494 | kgCO2e/USD | GB | 2022 | Cradle → gate S1 · S2 loc · S3↑ | defra_sic_2022 purchaser · USD 2022 | SIC 70. Native unit is GBP — converted to USD via static FX 0.79 GBP/USD for cross-source comparison. Recompute with accounting-period FX for production calculations. |
| 0.1180 | kgCO2e/GBP | GB | 2022 | Cradle → gate S1 · S2 loc · S3↑ | defra_sic_2022 purchaser · GBP 2022 | SIC 70. DEFRA consumption-based (UK MRIO) — captures imports unlike USEEIO production-based. |
| 0.1554 | kgCO2e/USD | NO | 2019 | Cradle → gate S1 · S2 loc · S3↑ | exiobase_3_8_2 basic · USD 2019 | EXIOBASE 3.8.2 "Other business services" (NACE 74 bundle) for NO. Broader than USEEIO NAICS 541610 — includes legal, advertising, R&D alongside management consulting. Converted EUR→USD at 2019 average FX 1.12. |
| 0.1740 | kgCO2e/EUR | NO | 2019 | Cradle → gate S1 · S2 loc · S3↑ | exiobase_3_8_2 basic · EUR 2019 | EXIOBASE 3.8.2 "Other business services" (NACE 74 bundle) for NO. Broader than USEEIO NAICS 541610 — includes legal, advertising, R&D alongside management consulting. |
| 0.1406 | kgCO2e/USD | PT | 2019 | Cradle → gate S1 · S2 loc · S3↑ | exiobase_3_8_2 basic · USD 2019 | EXIOBASE 3.8.2 "Other business services" (NACE 74 bundle) for PT. Broader than USEEIO NAICS 541610 — includes legal, advertising, R&D alongside management consulting. Converted EUR→USD at 2019 average FX 1.12. |
| 0.1575 | kgCO2e/EUR | PT | 2019 | Cradle → gate S1 · S2 loc · S3↑ | exiobase_3_8_2 basic · EUR 2019 | EXIOBASE 3.8.2 "Other business services" (NACE 74 bundle) for PT. Broader than USEEIO NAICS 541610 — includes legal, advertising, R&D alongside management consulting. |
| 0.1390 | kgCO2e/USD | AT | 2019 | Cradle → gate S1 · S2 loc · S3↑ | exiobase_3_8_2 basic · USD 2019 | EXIOBASE 3.8.2 "Other business services" (NACE 74 bundle) for AT. Broader than USEEIO NAICS 541610 — includes legal, advertising, R&D alongside management consulting. Converted EUR→USD at 2019 average FX 1.12. |
| 0.1557 | kgCO2e/EUR | AT | 2019 | Cradle → gate S1 · S2 loc · S3↑ | exiobase_3_8_2 basic · EUR 2019 | EXIOBASE 3.8.2 "Other business services" (NACE 74 bundle) for AT. Broader than USEEIO NAICS 541610 — includes legal, advertising, R&D alongside management consulting. |
| 0.1184 | kgCO2e/USD | CA | 2019 | Cradle → gate S1 · S2 loc · S3↑ | exiobase_3_8_2 basic · USD 2019 | EXIOBASE 3.8.2 "Other business services" (NACE 74 bundle) for CA. Broader than USEEIO NAICS 541610 — includes legal, advertising, R&D alongside management consulting. Converted EUR→USD at 2019 average FX 1.12. |
| 0.1326 | kgCO2e/EUR | CA | 2019 | Cradle → gate S1 · S2 loc · S3↑ | exiobase_3_8_2 basic · EUR 2019 | EXIOBASE 3.8.2 "Other business services" (NACE 74 bundle) for CA. Broader than USEEIO NAICS 541610 — includes legal, advertising, R&D alongside management consulting. |
| 0.1136 | kgCO2e/USD | DK | 2019 | Cradle → gate S1 · S2 loc · S3↑ | exiobase_3_8_2 basic · USD 2019 | EXIOBASE 3.8.2 "Other business services" (NACE 74 bundle) for DK. Broader than USEEIO NAICS 541610 — includes legal, advertising, R&D alongside management consulting. Converted EUR→USD at 2019 average FX 1.12. |
| 0.1272 | kgCO2e/EUR | DK | 2019 | Cradle → gate S1 · S2 loc · S3↑ | exiobase_3_8_2 basic · EUR 2019 | EXIOBASE 3.8.2 "Other business services" (NACE 74 bundle) for DK. Broader than USEEIO NAICS 541610 — includes legal, advertising, R&D alongside management consulting. |
| 0.0684 | kgCO2e/USD | CH | 2019 | Cradle → gate S1 · S2 loc · S3↑ | exiobase_3_8_2 basic · USD 2019 | EXIOBASE 3.8.2 "Other business services" (NACE 74 bundle) for CH. Broader than USEEIO NAICS 541610 — includes legal, advertising, R&D alongside management consulting. Converted EUR→USD at 2019 average FX 1.12. |
| 0.0766 | kgCO2e/EUR | CH | 2019 | Cradle → gate S1 · S2 loc · S3↑ | exiobase_3_8_2 basic · EUR 2019 | EXIOBASE 3.8.2 "Other business services" (NACE 74 bundle) for CH. Broader than USEEIO NAICS 541610 — includes legal, advertising, R&D alongside management consulting. |
| 0.0917 | kgCO2e/USD | JP | 2019 | Cradle → gate S1 · S2 loc · S3↑ | exiobase_3_8_2 basic · USD 2019 | EXIOBASE 3.8.2 "Other business services" (NACE 74 bundle) for JP. Broader than USEEIO NAICS 541610 — includes legal, advertising, R&D alongside management consulting. Converted EUR→USD at 2019 average FX 1.12. |
| 0.1027 | kgCO2e/EUR | JP | 2019 | Cradle → gate S1 · S2 loc · S3↑ | exiobase_3_8_2 basic · EUR 2019 | EXIOBASE 3.8.2 "Other business services" (NACE 74 bundle) for JP. Broader than USEEIO NAICS 541610 — includes legal, advertising, R&D alongside management consulting. |
| 0.1091 | kgCO2e/USD | NL | 2019 | Cradle → gate S1 · S2 loc · S3↑ | exiobase_3_8_2 basic · USD 2019 | EXIOBASE 3.8.2 "Other business services" (NACE 74 bundle) for NL. Broader than USEEIO NAICS 541610 — includes legal, advertising, R&D alongside management consulting. Converted EUR→USD at 2019 average FX 1.12. |
| 0.1222 | kgCO2e/EUR | NL | 2019 | Cradle → gate S1 · S2 loc · S3↑ | exiobase_3_8_2 basic · EUR 2019 | EXIOBASE 3.8.2 "Other business services" (NACE 74 bundle) for NL. Broader than USEEIO NAICS 541610 — includes legal, advertising, R&D alongside management consulting. |
| 0.1646 | kgCO2e/USD | IT | 2019 | Cradle → gate S1 · S2 loc · S3↑ | exiobase_3_8_2 basic · USD 2019 | EXIOBASE 3.8.2 "Other business services" (NACE 74 bundle) for IT. Broader than USEEIO NAICS 541610 — includes legal, advertising, R&D alongside management consulting. Converted EUR→USD at 2019 average FX 1.12. |
| 0.1843 | kgCO2e/EUR | IT | 2019 | Cradle → gate S1 · S2 loc · S3↑ | exiobase_3_8_2 basic · EUR 2019 | EXIOBASE 3.8.2 "Other business services" (NACE 74 bundle) for IT. Broader than USEEIO NAICS 541610 — includes legal, advertising, R&D alongside management consulting. |
| 0.0616 | kgCO2e/GBP | US | 2022 | Cradle → gate S1 · S2 loc · S3↑ | useeio_v1_3 purchaser · GBP 2022 | USEEIO commodity 541610, converted USD→GBP at static rate (0.79). For production, recompute with the accounting-period FX rate. |
| 0.0780 | kgCO2e/USD | US | 2022 | Cradle → gate S1 · S2 loc · S3↑ | useeio_v1_3 purchaser · USD 2022 | USEEIO commodity 541610. NAICS 541610. Purchaser price (with margins). Multiply 2022 USD spend × value to get kgCO2e. |
Other professional / scientific / technical services
| Value | Unit | Geo | Year | Scope | Source | Notes |
|---|---|---|---|---|---|---|
| 0.1911 | kgCO2e/USD | GB | 2022 | Cradle → gate S1 · S2 loc · S3↑ | defra_sic_2022 purchaser · USD 2022 | SIC 74. Native unit is GBP — converted to USD via static FX 0.79 GBP/USD for cross-source comparison. Recompute with accounting-period FX for production calculations. |
| 0.1510 | kgCO2e/GBP | GB | 2022 | Cradle → gate S1 · S2 loc · S3↑ | defra_sic_2022 purchaser · GBP 2022 | SIC 74. DEFRA consumption-based (UK MRIO) — captures imports unlike USEEIO production-based. |
| 0.0632 | kgCO2e/GBP | US | 2022 | Cradle → gate S1 · S2 loc · S3↑ | useeio_v1_3 purchaser · GBP 2022 | USEEIO commodity 5419A0, converted USD→GBP at static rate (0.79). For production, recompute with the accounting-period FX rate. |
| 0.0800 | kgCO2e/USD | US | 2022 | Cradle → gate S1 · S2 loc · S3↑ | useeio_v1_3 purchaser · USD 2022 | USEEIO commodity 5419A0. NAICS 541990. Purchaser price (with margins). Multiply 2022 USD spend × value to get kgCO2e. |
Activity-based (per physical unit) 27 categories · 27 factors
Multiply physical activity (passenger-km, kWh, room-night) by the factor to estimate kgCO2e. Gold standard — most accurate when you can collect the underlying activity data from invoices, expense reports, or operational systems.
Air travel — international (non-UK), economy
| Value | Unit | Geo | Year | Scope | Source | Notes |
|---|---|---|---|---|---|---|
| 0.1346 | kgCO2e/passenger.km | GLOBAL | 2024 | Well → wheel S3↑ | desnz_2024 | For flights that do not touch the UK. Used for non-UK-headquartered cohort firms reporting against the same DESNZ basis. |
Air travel — long-haul, business class
| Value | Unit | Geo | Year | Scope | Source | Notes |
|---|---|---|---|---|---|---|
| 0.5803 | kgCO2e/passenger.km | GB | 2024 | Well → wheel S3↑ | desnz_2024 | Business class assumed to consume ~3× the seat-area of economy. Use this for senior-staff long-haul. |
Air travel — long-haul, economy
| Value | Unit | Geo | Year | Scope | Source | Notes |
|---|---|---|---|---|---|---|
| 0.2001 | kgCO2e/passenger.km | GB | 2024 | Well → wheel S3↑ | desnz_2024 |
Air travel — long-haul, first class
| Value | Unit | Geo | Year | Scope | Source | Notes |
|---|---|---|---|---|---|---|
| 0.8004 | kgCO2e/passenger.km | GB | 2024 | Well → wheel S3↑ | desnz_2024 |
Air travel — long-haul, premium economy
| Value | Unit | Geo | Year | Scope | Source | Notes |
|---|---|---|---|---|---|---|
| 0.3201 | kgCO2e/passenger.km | GB | 2024 | Well → wheel S3↑ | desnz_2024 |
Air travel — short-haul, business class
| Value | Unit | Geo | Year | Scope | Source | Notes |
|---|---|---|---|---|---|---|
| 0.2743 | kgCO2e/passenger.km | GB | 2024 | Well → wheel S3↑ | desnz_2024 |
Air travel — short-haul, economy
| Value | Unit | Geo | Year | Scope | Source | Notes |
|---|---|---|---|---|---|---|
| 0.1829 | kgCO2e/passenger.km | GB | 2024 | Well → wheel S3↑ | desnz_2024 |
Air travel — UK domestic, average passenger
| Value | Unit | Geo | Year | Scope | Source | Notes |
|---|---|---|---|---|---|---|
| 0.2726 | kgCO2e/passenger.km | GB | 2024 | Well → wheel S3↑ | desnz_2024 | Includes 9% distance uplift + radiative forcing multiplier (~1.7×). |
Coach
| Value | Unit | Geo | Year | Scope | Source | Notes |
|---|---|---|---|---|---|---|
| 0.0272 | kgCO2e/passenger.km | GB | 2024 | Well → wheel S3↑ | desnz_2024 |
Hotel stay, France
| Value | Unit | Geo | Year | Scope | Source | Notes |
|---|---|---|---|---|---|---|
| 6.700 | kgCO2e/room-night | FR | 2024 | Use phase S3↑ | desnz_2024 | Low because FR grid is ~70% nuclear + ~25% renewable — among the lowest-carbon in Europe. |
Hotel stay, Germany
| Value | Unit | Geo | Year | Scope | Source | Notes |
|---|---|---|---|---|---|---|
| 13.20 | kgCO2e/room-night | DE | 2024 | Use phase S3↑ | desnz_2024 |
Hotel stay, India
| Value | Unit | Geo | Year | Scope | Source | Notes |
|---|---|---|---|---|---|---|
| 58.90 | kgCO2e/room-night | IN | 2024 | Use phase S3↑ | desnz_2024 | High because India grid is ~70% coal — air-conditioning load + grid mix push factor 5× FR. |
Hotel stay, Japan
| Value | Unit | Geo | Year | Scope | Source | Notes |
|---|---|---|---|---|---|---|
| 39.00 | kgCO2e/room-night | JP | 2024 | Use phase S3↑ | desnz_2024 |
Hotel stay, UAE
| Value | Unit | Geo | Year | Scope | Source | Notes |
|---|---|---|---|---|---|---|
| 63.80 | kgCO2e/room-night | AE | 2024 | Use phase S3↑ | desnz_2024 |
Hotel stay, UK
| Value | Unit | Geo | Year | Scope | Source | Notes |
|---|---|---|---|---|---|---|
| 10.40 | kgCO2e/room-night | GB | 2024 | Use phase S3↑ | desnz_2024 |
Hotel stay, UK (London)
| Value | Unit | Geo | Year | Scope | Source | Notes |
|---|---|---|---|---|---|---|
| 11.50 | kgCO2e/room-night | GB | 2024 | Use phase S3↑ | desnz_2024 |
Hotel stay, USA
| Value | Unit | Geo | Year | Scope | Source | Notes |
|---|---|---|---|---|---|---|
| 16.10 | kgCO2e/room-night | US | 2024 | Use phase S3↑ | desnz_2024 |
Natural gas — Scope 1 combustion (gross CV)
| Value | Unit | Geo | Year | Scope | Source | Notes |
|---|---|---|---|---|---|---|
| 0.1829 | kgCO2e/kWh | GB | 2024 | Use phase S1 | desnz_2024 | UK gas suppliers bill in kWh on a Gross CV basis by default — use this unless your invoice explicitly states Net CV. |
Natural gas — Scope 3 WTT (gross CV)
| Value | Unit | Geo | Year | Scope | Source | Notes |
|---|---|---|---|---|---|---|
| 0.0302 | kgCO2e/kWh | GB | 2024 | Well → tank S3↑ | desnz_2024 |
Rail — international (Eurostar)
| Value | Unit | Geo | Year | Scope | Source | Notes |
|---|---|---|---|---|---|---|
| 0.004460 | kgCO2e/passenger.km | EU | 2024 | Well → wheel S3↑ | desnz_2024 | Very low because Eurostar runs on French/UK grid mix dominated by nuclear + renewables. |
Rail — London Underground
| Value | Unit | Geo | Year | Scope | Source | Notes |
|---|---|---|---|---|---|---|
| 0.0278 | kgCO2e/passenger.km | GB | 2024 | Well → wheel S3↑ | desnz_2024 |
Rail — UK national
| Value | Unit | Geo | Year | Scope | Source | Notes |
|---|---|---|---|---|---|---|
| 0.0355 | kgCO2e/passenger.km | GB | 2024 | Well → wheel S3↑ | desnz_2024 |
Taxi — black cab
| Value | Unit | Geo | Year | Scope | Source | Notes |
|---|---|---|---|---|---|---|
| 0.2040 | kgCO2e/passenger.km | GB | 2024 | Well → wheel S3↑ | desnz_2024 |
Taxi — regular
| Value | Unit | Geo | Year | Scope | Source | Notes |
|---|---|---|---|---|---|---|
| 0.1486 | kgCO2e/passenger.km | GB | 2024 | Well → wheel S3↑ | desnz_2024 |
UK grid electricity — Scope 2 (location)
| Value | Unit | Geo | Year | Scope | Source | Notes |
|---|---|---|---|---|---|---|
| 0.2071 | kgCO2e/kWh | GB | 2024 | Use phase S2 loc | desnz_2024 | Use this for Scope 2 location-based reporting. For market-based, use supplier-specific or residual-mix factors instead. |
UK grid electricity — Scope 3 T&D losses
| Value | Unit | Geo | Year | Scope | Source | Notes |
|---|---|---|---|---|---|---|
| 0.0183 | kgCO2e/kWh | GB | 2024 | Use phase S3↑ | desnz_2024 |
UK grid electricity — Scope 3 well-to-tank
| Value | Unit | Geo | Year | Scope | Source | Notes |
|---|---|---|---|---|---|---|
| 0.0459 | kgCO2e/kWh | GB | 2024 | Well → tank S3↑ | desnz_2024 |
Reference factors are curated from the published sources at the indicated vintage and refreshed manually as new releases land. Apply with care: spend-based factors carry material uncertainty (often ±50%); activity-based factors require the right unit basis (e.g. gross vs net CV for natural gas, with-RF vs without-RF for air); product PCFs differ in lifecycle scope between vendors (Apple uses post-mitigation, others use pre-mitigation — we have aligned to pre-mitigation baselines for laptops). Re-check against the citation before any external-facing calculation.