Emission Factors API: DEFRA, EPA & Grid CO2e Calculator

Not affiliated with DESNZ/DEFRA, EPA, EEA or Ember; not an assurance of your reporting.

This emission factor lookup turns your activity data into kg CO2e with official, open emission factors: the UK Government GHG conversion factors (DESNZ, formerly DEFRA), the US EPA GHG Emission Factors Hub, EEA and Ember grid electricity factors, and EPA spend-based supply chain factors. Write the activity the way you have it ("500 km diesel van", "1200 kWh electricity Germany 2025", "3 t steel", "flight LHR-JFK economy") and get the factor, its scope and GHG Protocol category, the formula, the source table and year, the licence, the alternatives that were considered and an AI match score for the text-to-factor mapping.

Every factor value comes from an official file. Where a source publishes another unit, the value is converted in code and the row says so: EEA and Ember values are converted to kg CO2e/kWh (published as g CO2e/kWh), EPA eGRID values from lb per MWh and EPA waste values from metric tons. The AI only chooses among real factor rows and rates how well the chosen row fits your text. It never writes a number. For this step your activity text is sent to an external AI service for this fixed comparison only; turn off AI match score to use text similarity instead.

What does Emission Factor Lookup do?

1. Reads your activity. Quantity and unit ("1,200 kWh", "3 t", "200 miles", "$25,000"), country, US state or eGRID subregion, reporting year, cabin class and passengers are read in code. Structured input works too.
2. Finds the official factor. Fuels, company vehicles, freight, materials, waste, refrigerants, water, hotel stays, rail, taxi, bus and ferry travel come from DESNZ or the EPA hub. Grid electricity comes from DESNZ for the UK, EPA eGRID for the US, the EEA for EU countries and Ember for 200+ other countries. Flights use the DESNZ air factors and the great-circle distance between the two airports.
3. Calculates kg CO2e. Units are converted in code (miles to km, MWh to kWh, US gallons to litres, short tons to tonnes) and the formula is shown: 500 km x 0.25716 kg CO2e per km = 128.58 kg CO2e.
4. Documents it. Scope 1, 2 or 3, the GHG Protocol category, the dataset, publisher, year, table, row ID, source page, licence and attribution, plus an audit trail sentence you can paste into a CSRD, SECR or CDP methodology note.

Who uses it?

• Carbon accounting and ESG software teams that need a factor API with an audit trail behind every number.
• CSRD, SECR and CDP reporting teams turning fuel bills, meter readings, mileage claims and travel bookings into a Scope 1, 2 and 3 inventory.
• Logistics, procurement and travel managers estimating freight, purchase and flight emissions.
• AI agents and sustainability assistants that must answer "how much CO2e is this?" with a citable source.

What data you get

Field	What it is
status	calculated, factor_returned (no quantity given), not_found, needs_country, invalid_input or error
kgCO2e, tCO2e	The result in kg and tonnes CO2e
formula	Quantity x factor = result, in the factor's unit
factor.name	The official row, for example Delivery vehicles > Vans > Average (up to 3.5 tonnes) > Diesel
factor.value, factor.unit	The factor in kg CO2e, for example 0.25716 kg CO2e per km
factor.gasesKgCO2ePerUnit	CO2, CH4 and N2O parts of the factor, where the source publishes them
factor.otherUnits	The same factor in its other published units (litres, kWh, tonnes)
factor.scope, factor.ghgProtocolCategory	Scope 1, 2 or 3 and the category, for example Scope 3 Category 6: business travel
factor.dataset, publisher, datasetYear, table, rowId, sourceUrl	Where the number comes from
factor.licence, factor.licenceUrl, factor.attribution	Licence of the source, a link to the licence text and the attribution text to use
factor.conversionNote	For EEA and Ember grid factors: values converted to kg CO2e/kWh
factor.basis	Method notes, for example lifecycle versus combustion-only grid factors
quantity	Your quantity in the factor's unit, with the conversion
gasesKgCO2e	CO2, CH4 and N2O share of the result
matchScore, matchMethod	How well the factor row fits your activity (0 to 1) and how it was chosen
reviewRecommended	true when a person should check the choice before reporting
alternatives	Other rows that were considered, with their value and kg CO2e
upstreamFactors	Well-to-tank and grid loss factors of the same item (Scope 3 Category 3), with kg CO2e
flight	Airports, countries, great-circle km, DESNZ haul, cabin, passengers, return trip
yearRequested, yearUsed	The reporting year you asked for and the factor set used
auditTrail	One paragraph for your methodology appendix

Sources and licences

Source	What it covers	Years	Licence
UK Government GHG Conversion Factors for Company Reporting (DESNZ, formerly DEFRA), flat files	Fuels, bioenergy, refrigerants, cars, vans, HGVs, freight, rail, bus, taxi, ferry, flights, hotel stays, materials, waste, water, heat, UK electricity, well-to-tank, T&D	2014 to 2026	Open Government Licence v3.0 (www.nationalarchives.gov.uk/doc/open-government-licence/version/3)
US EPA GHG Emission Factors Hub	Stationary combustion, mobile CO2, non-road vehicles, eGRID electricity by subregion, steam, freight, waste, business travel	2022 onwards, as published	Public domain (US federal government work)
EEA, greenhouse gas emission intensity of electricity generation	EU-27 grid electricity by country	1990 onwards	CC BY 4.0, EEA legal notice (www.eea.europa.eu/en/legal-notice); values converted to kg CO2e/kWh
Ember Yearly Electricity Data	Grid electricity CO2 intensity for 200+ countries (lifecycle basis)	2000 onwards	CC BY 4.0 (creativecommons.org/licenses/by/4.0); values converted to kg CO2e/kWh
EPA Supply Chain GHG Emission Factors v1.3 (USEEIO)	Spend-based factors by NAICS industry, kg CO2e per 2022 US dollar	2022 dollars	Public domain (US federal government work)
OurAirports	Airport coordinates for flight distances	current	Public domain

The Actor downloads these official files, keeps a parsed copy for up to 30 days and refreshes it from the source after that. Paid databases (ecoinvent, IEA, Climatiq) are not used. The IPCC Emission Factor Database is not included because its terms do not allow commercial reuse without permission.

How to calculate emissions step by step

1. Open the Actor and put your activities into Activities, one per line, as text or objects.
2. Set a Default country if most of your data is from one country, and a Default reporting year.
3. Click Start. In our tests 40 activities took about 10 seconds and 188 activities under 70 seconds.
4. Download the results as JSON, CSV or Excel, or read them through the Apify API.

Input examples

{
  "activities": [
    "500 km diesel van",
    "1200 kWh electricity Germany 2025",
    "3 t steel",
    "flight LHR-JFK economy return",
    "$25,000 office furniture",
    {"reference": "INV-17", "category": "natural gas", "quantity": 18000, "unit": "kWh", "country": "UK", "year": 2025},
    {"reference": "T-9", "from": "FRA", "to": "SIN", "passengers": 2, "activity": "business class"}
  ],
  "defaultCountry": "UK"
}

Recognised units include kWh, MWh, GJ, therms, mmBtu, litres, cubic metres, US and UK gallons, scf, kg, tonnes, short tons, lb, km, miles, passenger.km, tonne.km, ton-miles, room nights, FTE working hours and USD.

Example output

{
  "reference": "1",
  "activity": "500 km diesel van",
  "status": "calculated",
  "kgCO2e": 128.58,
  "tCO2e": 0.12858,
  "formula": "500 km x 0.25716 kg CO2e per km = 128.5800 kg CO2e",
  "factor": {
    "name": "Delivery vehicles > Vans > Average (up to 3.5 tonnes) > Diesel",
    "value": 0.25716,
    "unit": "kg CO2e per km",
    "scope": "1",
    "ghgProtocolCategory": "Scope 1: mobile combustion (company-owned or controlled vehicles)",
    "dataset": "UK Government GHG Conversion Factors for Company Reporting",
    "datasetYear": 2026,
    "table": "Factors by Category",
    "rowId": "5_303_3102_4",
    "licence": "Open Government Licence v3.0"
  },
  "matchScore": 0.92,
  "matchMethod": "AI match over official factor rows",
  "reviewRecommended": false,
  "alternatives": [
    {"name": "Delivery vehicles > Vans > Class III (1.74 to 3.5 tonnes) > Diesel", "value": 0.28046, "kgCO2e": 140.23}
  ],
  "upstreamFactors": [
    {"name": "WTT- delivery vehs & freight > WTT- vans > Average (up to 3.5 tonnes) > Diesel", "value": 0.06128, "kgCO2e": 30.64}
  ]
}

How the factor choice works

• Rules in code decide grid electricity (by country and year), flights (airport distance, DESNZ haul definition, cabin class, radiative forcing) and hotel stays (by country).
• For everything else code lists the official rows that fit your unit, an AI picks the kind of factor and then the best row, and rates how well that row fits your text from 0 to 1. Code then decides: below 0.5 the row is reported as not_found with the closest rows as alternatives and is not charged; from 0.5 to 0.7 reviewRecommended is true.
• US activities search the EPA hub first and UK and other activities search DESNZ first; the other set is searched when the first has no good match. You can change this with Preferred factor set.
• The reporting year picks the factor set of that year. When it is not published yet, the latest earlier set is used and the note says so.

API use

curl -X POST "https://api.apify.com/v2/acts/reliable_tools~emission-factors-api/run-sync-get-dataset-items?token=YOUR_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{"activities": ["10000 litres diesel 2025", "5000 kWh electricity UK 2025"]}'

from apify_client import ApifyClient

client = ApifyClient("YOUR_TOKEN")
run = client.actor("reliable_tools/emission-factors-api").call(run_input={
    "activities": ["500 km diesel van", "flight LHR-JFK economy"]})
for row in client.dataset(run["defaultDatasetId"]).iterate_items():
    print(row["activity"], row["kgCO2e"], row["factor"]["name"] if row["factor"] else row["note"])

Pricing

Pay per event, no subscription:

Event	Price
Activity calculated (factor, kg CO2e, formula, scope, source, alternatives, audit trail)	$0.02
Factor returned (activity without a quantity)	$0.005
Actor start	$0.00005 per run

Rows with no suitable factor, a missing country, invalid input or a source error are free.

FAQ

Where do the DEFRA conversion factors come from? Data copied from the UK Government's public GHG conversion factor flat files on GOV.UK; not affiliated with or endorsed by DESNZ/DEFRA. Since 2023 the UK factors are published by the Department for Energy Security and Net Zero (DESNZ); they are the same series that used to be called DEFRA factors. The Actor reads the flat file of each year from 2014 to 2026. The results support your reporting but are not an assurance of it.

Which electricity factor do I get? A location-based Scope 2 factor: DESNZ for the UK, EPA eGRID for the US (by state or subregion when you name one, else the US average), the EEA for EU countries and Ember for other countries. Ember factors are lifecycle factors and are higher than combustion-only factors; the basis field says which one you got. For market-based Scope 2 use your supplier's factor.

Does it include well-to-tank and grid losses? They are always listed under upstreamFactors with their kg CO2e. Turn on Add upstream emissions to the total to add them to kgCO2e.

How are flight emissions calculated? Great-circle distance between the two IATA airports, the DESNZ haul (domestic, short-haul, long-haul or international between non-UK airports) and cabin class. The DESNZ factors already include an 8 percent distance uplift, so none is added. Radiative forcing is included by default, as DESNZ recommends.

What if my van is not company-owned? Pass "scope": 3 on the activity. The factor stays the same and the result is reported as Scope 3 (Category 4 for vans and HGVs, Category 6 for cars).

Can I use spend data? Yes, in US dollars: "$25,000 office furniture" uses the EPA spend-based factor of the matching NAICS industry, per 2022 dollar at purchaser price. Other currencies are not converted.

How accurate is the match? We tested 40 activities across fuels, vehicles, freight, materials, waste, electricity in 10 countries, flights, hotels and spend, and checked factor values by hand against the official spreadsheets. Rows with a lower match score are flagged with reviewRecommended, and spend categories that sit close together (for example furniture makers and furniture wholesalers) can swap, so check the alternatives before you report.

Something missing or wrong? Open an issue on the Issues tab and we will look at it.

About Reliable Tools

This Actor is made by Reliable Tools. We build data tools that return clean, sourced data plus an AI label with a confidence score, so you can filter and act on the results straight away.

If a factor is missing or an activity does not match the way you expect, open an issue on the Issues tab. We read every one and usually reply within a day. You can find our other Actors on our profile page.