Convert CO2e per £/$/€ of Spend (PCAF)
Spend-based emission factors — the kilograms of CO2e attached to each unit of money spent — are the backbone of PCAF financed-emissions and Scope 3 Category 1 screening. But the most widely used dataset (the US EPA’s environmentally-extended input-output factors) is quoted per US dollar, while UK and European spend sits in pounds and euros. This converter re-expresses a spend factor from one currency basis to another. It changes the currency only: it does not look up a sector factor or compute a footprint — that is the spend-based calculator’s job, linked below.
To convert a spend-based emission factor between currencies, multiply by the exchange rate. From per US dollar: × 1.27 for per pound, × 1.08 for per euro (reference mid-rates). So 0.30 kg CO2e/$ ≈ 0.38 kg CO2e/£ or 0.32 kg CO2e/€. Because spend factors carry ±30–50% uncertainty, the exact FX rate rarely changes the conclusion.
A US EEIO emission factor for a spend category is 0.30 kg CO2e per US dollar. Re-expressed per pound and per euro at reference rates:
| Currency basis | Calculation | Result |
|---|---|---|
| Per US dollar | — | 0.30 kg CO2e/$ |
| Per pound (× 1.27) | 0.30 × 1.27 | 0.381 kg CO2e/£ |
| Per euro (× 1.08) | 0.30 × 1.08 | 0.324 kg CO2e/€ |
The per-pound figure is higher because a pound is more money than a dollar, so it carries more embedded emissions.
How to convert a spend-based emission factor between currencies
A spend-based factor is emissions per unit of currency, so converting its basis is an exchange-rate multiplication: a factor per US dollar becomes a factor per pound by multiplying by the dollars-per-pound rate. The pound and euro figures come out larger than the dollar figure simply because each is worth more than a dollar.
The formula
kg CO2e/£ = kg CO2e/$ × (USD per GBP)
kg CO2e/€ = kg CO2e/$ × (USD per EUR)
The rates used here are reference mid-rates — approximately 1 GBP ≈ 1.27 USD and 1 EUR ≈ 1.08 USD (illustrative, 2026). Exchange rates move daily, so use a current rate for exact work. But spend-based factors themselves carry roughly ±30–50% uncertainty (see PCAF data quality), which dwarfs any FX drift — chasing the FX rate to four decimals while the underlying factor is a broad estimate is false precision.
Converting back: per £ or € to per $
To go from a per-pound or per-euro factor back to per US dollar, divide by the same rate. Use the swap control on the converter above to reverse direction, and the currency toggle to pick the target.
kg CO2e/$ = kg CO2e/£ ÷ 1.27
Spend-based factor conversion table
The columns apply the reference rates × 1.27 (GBP) and × 1.08 (EUR).
| kg CO2e/$ | kg CO2e/£ | kg CO2e/€ |
|---|---|---|
| 0.05 | 0.064 | 0.054 |
| 0.1 | 0.127 | 0.108 |
| 0.2 | 0.254 | 0.216 |
| 0.3 | 0.381 | 0.324 |
| 0.5 | 0.635 | 0.540 |
| 1 | 1.270 | 1.080 |
What is a spend-based (EEIO) emission factor?
A spend-based factor estimates emissions from the money spent on a good or service rather than its physical quantity. It comes from an environmentally-extended input-output (EEIO) model, which links each sector of an economy to the emissions embedded in a unit of its output. Multiply spend by the factor and you get a screening estimate of the associated CO2e — the method PCAF calls economic-activity-based, and the fallback for Scope 3 Category 1 when supplier-specific data is unavailable.
Spend-based factors vary enormously by sector — from under 0.1 kg CO2e per dollar for low-impact professional services to well over 1 kg CO2e per dollar for energy-intensive materials — with broad economy-wide averages in the region of 0.2–0.3 kg CO2e per dollar. The authoritative datasets are the US EPA Supply Chain (USEEIO) factors, quoted per US dollar, and the multi-region EXIOBASE, used across currencies.
Why the currency basis matters
Grid and fuel factors are physical and travel across borders unchanged. Spend factors do not: they are denominated in a currency, so a US EEIO factor per dollar and a UK spend figure in pounds cannot be combined until they share a currency. That is the one conversion this page performs.
Re-basing a US per-dollar factor into pounds gives you the same US economic structure priced in pounds — not a genuine UK or EU factor. Different economies have different energy mixes and price levels, so a native EXIOBASE Europe factor will differ from a currency-converted US one. Use the currency conversion for quick reconciliation; use a region-specific dataset when the geography is material.
Spend-based means lower data quality
Under PCAF’s data-quality score, spend-based and economic-activity estimates sit at the lower end (scores 4–5). They are ideal for screening — covering every category cheaply to find the hotspots — but material categories should be upgraded to supplier-specific or activity-based data. Treat a spend-based number as an order-of-magnitude signal, not a precise figure, which is exactly why the exchange-rate precision is a second-order concern.
Where spend-based factors and currency bases appear
- US EPA Supply Chain (USEEIO) — the standard US spend-based factor set, published per US dollar.
- EXIOBASE — a multi-region input-output database used for spend-based factors across currencies and countries.
- PCAF — the economic-activity-based method for financed emissions relies on spend/revenue factors.
- GHG Protocol Scope 3 — the spend-based method is the screening default for Category 1 (purchased goods and services).
Ready to turn spend into an actual emissions estimate — sector spend × the right EEIO factor — rather than just converting the factor’s currency?
Frequently Asked Questions
Multiply by the exchange rate. From per US dollar, use × 1.27 for per pound and × 1.08 for per euro (reference mid-rates). For example, 0.30 kg CO2e/$ ≈ 0.38 kg CO2e/£. To reverse, divide by the same rate.
It estimates emissions from the money spent on a good or service, using an environmentally-extended input-output (EEIO) model that links each economic sector to the CO2e embedded in a unit of its output. Spend × factor gives a screening estimate — PCAF’s economic-activity-based method and the Scope 3 Category 1 fallback when supplier data is unavailable.
Spend-based factors carry roughly ±30–50% uncertainty (PCAF data-quality scores 4–5), so a few percent of exchange-rate drift is immaterial to the result. A disclosed reference rate keeps the conversion transparent without implying false precision. For an exact figure, apply your reporting period’s own rate.
It ranges widely by sector — under 0.1 kg CO2e per dollar for low-impact services to over 1 kg CO2e per dollar for energy-intensive goods — with economy-wide averages around 0.2–0.3 kg CO2e per dollar. Use the specific sector factor from a dataset like USEEIO or EXIOBASE rather than a generic average.
Use spend-based factors for screening — cheap, complete coverage to find your emissions hotspots. Upgrade material categories to supplier-specific or activity-based (physical-quantity) data, which is more accurate and scores better under PCAF data quality. Most inventories combine both: spend-based for the long tail, activity-based for the big items.
Divide by the rate: kg CO2e/$ = kg CO2e/£ ÷ 1.27 (or ÷ 1.08 for euros). For example, 0.381 kg CO2e/£ ÷ 1.27 = 0.30 kg CO2e/$. Use the swap control on the converter to reverse direction.
No — it only converts a factor between currency bases. To turn spend into an emissions estimate you multiply each category’s spend by its sector EEIO factor; use the spend-based Scope 3 Category 1 calculator for that, which applies the correct sector factors and PCAF data-quality scoring.