What does each factor record?

The value and unit, which gases it covers, the scope, the category and activity, the edition it belongs to and the published file it was taken from, which is what an auditor asks for.

Why are factors keyed on a slug rather than a DEFRA id?

DEFRA ids change between years. A semantic slug stays stable across editions, so a factor you used in 2024 resolves to the same activity in 2026 and the updates endpoint shows what changed.

Can the API do the multiplication?

Yes. The calculate endpoint takes an activity amount and a factor and returns emissions by gas and total CO2e, and the POST form handles many line items in one call.

How often is it updated?

When DEFRA or the EPA publish a new edition, typically once a year each. Earlier editions stay available for restatements.

DataMAINTAINED1 token / call

Emission Factors API

13,000 DEFRA and EPA greenhouse-gas emission factors with gases, units and the published file they came from

Authoritative greenhouse-gas emission factors with the provenance a reporting team actually needs to cite: 13,000+ factors covering Scope 1, 2 and 3, drawn from four editions (2023-2026) of the UK DEFRA/DESNZ conversion factors and the US EPA GHG Emission Factors Hub. Fuels, UK and US grid electricity (including every eGRID subregion), passenger and delivery vehicles by size and fuel, freight by mode and tonne.km, flights by haul and cabin class, rail, sea, hotel stays, homeworking, water supply and treatment, material use, waste by disposal route, and refrigerants with their AR5 global warming potentials. Every factor carries kg CO2e per unit plus the CO2 / CH4 / N2O split, the gases it actually covers, whether the CO2e was published or derived, the GWP basis used, and the exact source file and licence it came from. Because the API keys on a stable semantic slug rather than the publisher's own row id — which is not stable between editions — you can pull the same activity across years to restate a prior reporting period. A calculate endpoint turns activity data into kg CO2e in one call, single or batched, totalled by scope, keeping biogenic CO2 out of the scope totals and warning when a factor covers only some gases. A weekly job re-checks each publisher and records whether the file behind every edition is still the one we parsed, exposed at /v1/factors/updates so you can verify the dataset is current rather than take it on trust. Self-hosted dataset built from free, redistributable government sources — no third-party calls at request time.

Every call needs an X-Api-Key header. A free key includes 500 tokens a month, no card required. 1 token per call, so the free plan covers about 500 calls a month.

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response.json

{
  "slug": "uk-electricity-electricity-generated-electricity-uk-kwh-kwh",
  "label": "UK electricity - Electricity generated - Electricity: UK",
  "year": 2026,
  "scope": "Scope 2",
  "co2e": {
    "total": 0.13096,
    "unit": "kg CO2e",
    "per": "kWh",
    "basis": "published",
    "gases_included": [
      "CO2",
      "CH4",
      "N2O"
    ]
  },
  "source": {
    "publisher": "UK Department for Energy Security and Net Zero / Defra",
    "licence": "Open Government Licence v3.0"
  }
}

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Use cases for Emission Factors API

Compute Scope 1, 2 and 3 emissions for fuels, electricity, travel and freight with factors you can cite in a CSRD or GHG Protocol report.
Pick the right UK or US grid factor, including every eGRID subregion, for a facility's electricity.
Convert flights by haul and cabin class, hotel nights or tonne-kilometres of freight into CO2e.
Track which factors changed between editions to restate prior-year figures correctly.

Emission Factors API endpoints

Every endpoint with its parameters and a real example response.

GETCalculate Emissions
POSTCalculate Emissions Batch
GETFactor Categories
GETFactor Sets
GETFactor Units
GETGet Factor
GETGlobal Warming Potentials
GETList Factors
GETRandom Factor
GETSource Freshness

GETCalculate Emissions

https://api-emission-factors.dataandapis.com/v1/calculate

Query parameters

Parameter	Example
factor	uk-electricity-electricity-generated-electricity-uk-kwh-kwh	Required
publisher	DEFRA	Optional
quantity	1200	Required
year	2026	Optional

Example request

curl "https://api-emission-factors.dataandapis.com/v1/calculate?factor=uk-electricity-electricity-generated-electricity-uk-kwh-kwh&publisher=DEFRA&quantity=1200&year=2026" \
  -H "X-Api-Key: YOUR_API_KEY"

Example response

{
  "total_kg_co2e": 157.152,
  "total_tonnes_co2e": 0.157152,
  "by_scope": {
    "Scope 2": 157.152
  },
  "biogenic_kg_co2e": 0,
  "count": 1,
  "failed": 0,
  "items": [
    {
      "ok": true,
      "factor": "uk-electricity-electricity-generated-electricity-uk-kwh-kwh",
      "label": "UK electricity - Electricity generated - Electricity: UK - kWh",
      "quantity": 1200,
      "unit": "kWh",
      "factor_value": 0.13096,
      "kg_co2e": 157.152,
      "by_gas": {
        "co2": 155.31599999999997,
        "ch4": 0.804,
        "n2o": 1.032
      },
      "scope": "Scope 2",
      "biogenic": false,
      "warnings": [],
      "source": {
        "set": "defra-2026",
…

Show full response

{
  "total_kg_co2e": 157.152,
  "total_tonnes_co2e": 0.157152,
  "by_scope": {
    "Scope 2": 157.152
  },
  "biogenic_kg_co2e": 0,
  "count": 1,
  "failed": 0,
  "items": [
    {
      "ok": true,
      "factor": "uk-electricity-electricity-generated-electricity-uk-kwh-kwh",
      "label": "UK electricity - Electricity generated - Electricity: UK - kWh",
      "quantity": 1200,
      "unit": "kWh",
      "factor_value": 0.13096,
      "kg_co2e": 157.152,
      "by_gas": {
        "co2": 155.31599999999997,
        "ch4": 0.804,
        "n2o": 1.032
      },
      "scope": "Scope 2",
      "biogenic": false,
      "warnings": [],
      "source": {
        "set": "defra-2026",
        "publisher": "UK Department for Energy Security and Net Zero / Defra",
        "edition_year": 2026,
        "basis": "published",
        "gwp_set": "IPCC AR5 (100-year)",
        "gases_included": [
          "CO2",
          "CH4",
          "N2O"
        ],
        "licence": "Open Government Licence v3.0",
        "source_url": "https://www.gov.uk/government/publications/greenhouse-gas-reporting-conversion-factors-2026"
      }
    }
  ]
}

POSTCalculate Emissions Batch

https://api-emission-factors.dataandapis.com/v1/calculate

This endpoint takes no parameters.

Example request

curl -X POST "https://api-emission-factors.dataandapis.com/v1/calculate" \
  -H "X-Api-Key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{}'

Example response

{
  "total_kg_co2e": 3896.706,
  "total_tonnes_co2e": 3.896706,
  "by_scope": {
    "Scope 2": 1571.52,
    "Scope 1": 2325.186
  },
  "biogenic_kg_co2e": 0,
  "count": 2,
  "failed": 0,
  "items": [
    {
      "ok": true,
      "factor": "uk-electricity-electricity-generated-electricity-uk-kwh-kwh",
      "label": "Office electricity",
      "quantity": 12000,
      "unit": "kWh",
      "factor_value": 0.13096,
      "kg_co2e": 1571.52,
      "by_gas": {
        "co2": 1553.1599999999999,
        "ch4": 8.040000000000001,
        "n2o": 10.32
      },
      "scope": "Scope 2",
      "biogenic": false,
      "warnings": [],
      "source": {
…

Show full response

{
  "total_kg_co2e": 3896.706,
  "total_tonnes_co2e": 3.896706,
  "by_scope": {
    "Scope 2": 1571.52,
    "Scope 1": 2325.186
  },
  "biogenic_kg_co2e": 0,
  "count": 2,
  "failed": 0,
  "items": [
    {
      "ok": true,
      "factor": "uk-electricity-electricity-generated-electricity-uk-kwh-kwh",
      "label": "Office electricity",
      "quantity": 12000,
      "unit": "kWh",
      "factor_value": 0.13096,
      "kg_co2e": 1571.52,
      "by_gas": {
        "co2": 1553.1599999999999,
        "ch4": 8.040000000000001,
        "n2o": 10.32
      },
      "scope": "Scope 2",
      "biogenic": false,
      "warnings": [],
      "source": {
        "set": "defra-2026",
        "publisher": "UK Department for Energy Security and Net Zero / Defra",
        "edition_year": 2026,
        "basis": "published",
        "gwp_set": "IPCC AR5 (100-year)",
        "gases_included": [
          "CO2",
          "CH4",
          "N2O"
        ],
        "licence": "Open Government Licence v3.0",
        "source_url": "https://www.gov.uk/government/publications/greenhouse-gas-reporting-conversion-factors-2026"
      }
    },
    {
      "ok": true,
      "factor": "fuels-liquid-fuels-diesel-average-biofuel-blend-litres",
      "label": "Fleet diesel",
      "quantity": 900,
      "unit": "litres",
      "factor_value": 2.58354,
      "kg_co2e": 2325.186,
      "by_gas": {
        "co2": 2295.315,
        "ch4": 0.261,
        "n2o": 29.61
      },
      "scope": "Scope 1",
      "biogenic": false,
      "warnings": [],
      "source": {
        "set": "defra-2026",
        "publisher": "UK Department for Energy Security and Net Zero / Defra",
        "edition_year": 2026,
        "basis": "published",
        "gwp_set": "IPCC AR5 (100-year)",
        "gases_included": [
          "CO2",
          "CH4",
          "N2O"
        ],
        "licence": "Open Government Licence v3.0",
        "source_url": "https://www.gov.uk/government/publications/greenhouse-gas-reporting-conversion-factors-2026"
      }
    }
  ]
}

GETFactor Categories

https://api-emission-factors.dataandapis.com/v1/factors/categories

Query parameters

Parameter	Example
publisher	DEFRA	Optional
scope	Scope 3	Optional
year	2026	Optional

Example request

curl "https://api-emission-factors.dataandapis.com/v1/factors/categories?publisher=DEFRA&scope=Scope%203&year=2026" \
  -H "X-Api-Key: YOUR_API_KEY"

Example response

{
  "count": 108,
  "categories": [
    {
      "category": "Bioenergy",
      "subcategory": "Biofuel",
      "scope": "Scope 1",
      "count": 37
    },
    {
      "category": "Bioenergy",
      "subcategory": "Biogas",
      "scope": "Scope 1",
      "count": 4
    },
    {
      "category": "Bioenergy",
      "subcategory": "Biomass",
      "scope": "Scope 1",
      "count": 8
    }
  ]
}

GETFactor Sets

https://api-emission-factors.dataandapis.com/v1/factors/sets

This endpoint takes no parameters.

Example request

curl "https://api-emission-factors.dataandapis.com/v1/factors/sets" \
  -H "X-Api-Key: YOUR_API_KEY"

Example response

{
  "count": 5,
  "sets": [
    {
      "set": "defra-2026",
      "publisher": "DEFRA",
      "publisher_full": "UK Department for Energy Security and Net Zero / Defra",
      "title": "Greenhouse gas reporting: conversion factors 2026",
      "edition_year": 2026,
      "region": "UK",
      "licence": "Open Government Licence v3.0",
      "gwp_set": "IPCC AR5 (100-year)",
      "source_url": "https://www.gov.uk/government/publications/greenhouse-gas-reporting-conversion-factors-2026",
      "file_url": "https://assets.publishing.service.gov.uk/media/6a6c9748862aaf18d9c62ac9/ghg-conversion-factors-2026-flat-format-revised.xlsx",
      "published_at": "2026-07-31",
      "retrieved_at": "2026-08-27",
      "factor_count": 3129,
      "upstream": {
        "status": "current",
        "last_checked": "2026-08-27 13:36:52",
        "current_file_url": null
      }
    },
    {
      "set": "defra-2025",
      "publisher": "DEFRA",
      "publisher_full": "UK Department for Energy Security and Net Zero / Defra",
      "title": "Greenhouse gas reporting: conversion factors 2025",
…

Show full response

{
  "count": 5,
  "sets": [
    {
      "set": "defra-2026",
      "publisher": "DEFRA",
      "publisher_full": "UK Department for Energy Security and Net Zero / Defra",
      "title": "Greenhouse gas reporting: conversion factors 2026",
      "edition_year": 2026,
      "region": "UK",
      "licence": "Open Government Licence v3.0",
      "gwp_set": "IPCC AR5 (100-year)",
      "source_url": "https://www.gov.uk/government/publications/greenhouse-gas-reporting-conversion-factors-2026",
      "file_url": "https://assets.publishing.service.gov.uk/media/6a6c9748862aaf18d9c62ac9/ghg-conversion-factors-2026-flat-format-revised.xlsx",
      "published_at": "2026-07-31",
      "retrieved_at": "2026-08-27",
      "factor_count": 3129,
      "upstream": {
        "status": "current",
        "last_checked": "2026-08-27 13:36:52",
        "current_file_url": null
      }
    },
    {
      "set": "defra-2025",
      "publisher": "DEFRA",
      "publisher_full": "UK Department for Energy Security and Net Zero / Defra",
      "title": "Greenhouse gas reporting: conversion factors 2025",
      "edition_year": 2025,
      "region": "UK",
      "licence": "Open Government Licence v3.0",
      "gwp_set": "IPCC AR5 (100-year)",
      "source_url": "https://www.gov.uk/government/publications/greenhouse-gas-reporting-conversion-factors-2025",
      "file_url": "https://assets.publishing.service.gov.uk/media/6846b6ea57f3515d9611f0dd/ghg-conversion-factors-2025-flat-format.xlsx",
      "published_at": "2025-06-10",
      "retrieved_at": "2026-08-27",
      "factor_count": 3123,
      "upstream": {
        "status": "current",
        "last_checked": "2026-08-27 13:36:52",
        "current_file_url": null
      }
    }
  ]
}

GETFactor Units

https://api-emission-factors.dataandapis.com/v1/factors/units

Query parameters

Parameter	Example
publisher	DEFRA	Optional
year	2026	Optional

Example request

curl "https://api-emission-factors.dataandapis.com/v1/factors/units?publisher=DEFRA&year=2026" \
  -H "X-Api-Key: YOUR_API_KEY"

Example response

{
  "count": 18,
  "units": [
    {
      "unit": "km",
      "output_unit": "kg CO2e",
      "kind": "emission",
      "count": 702
    },
    {
      "unit": "miles",
      "output_unit": "kg CO2e",
      "kind": "emission",
      "count": 617
    },
    {
      "unit": "kg",
      "output_unit": "kg CO2e",
      "kind": "emission",
      "count": 398
    },
    {
      "unit": "tonnes",
      "output_unit": "kg CO2e",
      "kind": "emission",
      "count": 292
    }
  ]
…

Show full response

{
  "count": 18,
  "units": [
    {
      "unit": "km",
      "output_unit": "kg CO2e",
      "kind": "emission",
      "count": 702
    },
    {
      "unit": "miles",
      "output_unit": "kg CO2e",
      "kind": "emission",
      "count": 617
    },
    {
      "unit": "kg",
      "output_unit": "kg CO2e",
      "kind": "emission",
      "count": 398
    },
    {
      "unit": "tonnes",
      "output_unit": "kg CO2e",
      "kind": "emission",
      "count": 292
    }
  ]
}

GETGet Factor

https://api-emission-factors.dataandapis.com/v1/factors/{slug}

Path parameters

Parameter	Example
slug	uk-electricity-electricity-generated-electricity-uk-kwh-kwh	Required

Query parameters

Parameter	Example
publisher	DEFRA	Optional
year	2026	Optional

Example request

curl "https://api-emission-factors.dataandapis.com/v1/factors/uk-electricity-electricity-generated-electricity-uk-kwh-kwh?publisher=DEFRA&year=2026" \
  -H "X-Api-Key: YOUR_API_KEY"

Example response

{
  "slug": "uk-electricity-electricity-generated-electricity-uk-kwh-kwh",
  "label": "UK electricity - Electricity generated - Electricity: UK - kWh",
  "publisher": "DEFRA",
  "year": 2026,
  "region": "UK",
  "scope": "Scope 2",
  "category": "UK electricity",
  "subcategory": "Electricity generated",
  "activity": "Electricity: UK",
  "detail": "kWh",
  "unit": "kWh",
  "kind": "emission",
  "value": 0.13096,
  "output_unit": "kg CO2e",
  "gases": [
    "CO2",
    "CH4",
    "N2O"
  ],
  "variant": null,
  "biogenic": false,
  "co2e": {
    "total": 0.13096,
    "unit": "kg CO2e",
    "per": "kWh",
    "basis": "published",
    "gases_included": [
…

Show full response

{
  "slug": "uk-electricity-electricity-generated-electricity-uk-kwh-kwh",
  "label": "UK electricity - Electricity generated - Electricity: UK - kWh",
  "publisher": "DEFRA",
  "year": 2026,
  "region": "UK",
  "scope": "Scope 2",
  "category": "UK electricity",
  "subcategory": "Electricity generated",
  "activity": "Electricity: UK",
  "detail": "kWh",
  "unit": "kWh",
  "kind": "emission",
  "value": 0.13096,
  "output_unit": "kg CO2e",
  "gases": [
    "CO2",
    "CH4",
    "N2O"
  ],
  "variant": null,
  "biogenic": false,
  "co2e": {
    "total": 0.13096,
    "unit": "kg CO2e",
    "per": "kWh",
    "basis": "published",
    "gases_included": [
      "CO2",
      "CH4",
      "N2O"
    ],
    "by_gas": {
      "co2": 0.12943,
      "ch4": 0.00067,
      "n2o": 0.00086
    }
  },
  "gas_mass": {
    "unit": "kg",
    "per": "kWh",
    "co2": null,
    "ch4": null,
    "n2o": null
  },
  "energy": null,
  "gwp_set": "IPCC AR5 (100-year)",
  "source": {
    "set": "defra-2026",
    "publisher": "UK Department for Energy Security and Net Zero / Defra",
    "title": "Greenhouse gas reporting: conversion factors 2026",
    "edition_year": 2026,
    "licence": "Open Government Licence v3.0",
    "source_url": "https://www.gov.uk/government/publications/greenhouse-gas-reporting-conversion-factors-2026",
    "file_url": "https://assets.publishing.service.gov.uk/media/6a6c9748862aaf18d9c62ac9/ghg-conversion-factors-2026-flat-format-revised.xlsx",
    "published_at": "2026-07-31",
    "retrieved_at": "2026-08-27",
    "publisher_row_id": "7_400_4000_5_1,7_400_4000_5_2,7_400_4000_5_3,7_400_4000_5_4"
  },
  "raw": {
    "ids": [
      "7_400_4000_5_1",
      "7_400_4000_5_2",
      "7_400_4000_5_3",
      "7_400_4000_5_4"
    ],
    "ghg_units": {
      "kg CO2e": 0.13096,
      "kg CO2e of CO2 per unit": 0.12943,
      "kg CO2e of CH4 per unit": 0.00067,
      "kg CO2e of N2O per unit": 0.00086
    }
  },
  "history": [
    {
      "year": 2026,
      "value": 0.13096,
      "unit": "kWh",
      "basis": "published"
    },
    {
      "year": 2025,
      "value": 0.177,
      "unit": "kWh",
      "basis": "published"
    },
    {
      "year": 2024,
      "value": 0.20705,
      "unit": "kWh",
      "basis": "published"
    },
    {
      "year": 2023,
      "value": 0.20707428859060403,
      "unit": "kWh",
      "basis": "published"
    }
  ]
}

GETGlobal Warming Potentials

https://api-emission-factors.dataandapis.com/v1/factors/gwp

Query parameters

Parameter	Example
blend	true	Optional
gas	R-410A	Optional

Example request

curl "https://api-emission-factors.dataandapis.com/v1/factors/gwp?blend=true&gas=R-410A" \
  -H "X-Api-Key: YOUR_API_KEY"

Example response

{
  "count": 1,
  "gwp": [
    {
      "gas": "R-410A",
      "name": "R-410A",
      "formula": "50% HFC-32 , 50% HFC-125",
      "gwp_100": 1924,
      "assessment": "IPCC AR5",
      "blend": 1
    }
  ]
}

GETList Factors

https://api-emission-factors.dataandapis.com/v1/factors

Query parameters

Parameter	Example
activity	Diesel	Optional
biogenic	false	Optional
category	Fuels	Optional
gas	CH4	Optional
kind	emission	Optional
limit	20	Optional
page	1	Optional
publisher	DEFRA	Optional
q	diesel	Optional
region	UK	Optional
scope	Scope 1	Optional
set	defra-2026	Optional
subcategory	Liquid fuels	Optional
unit	litres	Optional
year	2026	Optional

Example request

curl "https://api-emission-factors.dataandapis.com/v1/factors?activity=Diesel&biogenic=false&category=Fuels&gas=CH4&kind=emission&limit=20&page=1&publisher=DEFRA&q=diesel&region=UK&scope=Scope%201&set=defra-2026&subcategory=Liquid%20fuels&unit=litres&year=2026" \
  -H "X-Api-Key: YOUR_API_KEY"

Example response

{
  "total": 23,
  "page": 1,
  "limit": 2,
  "count": 2,
  "results": [
    {
      "slug": "bioenergy-biofuel-biodiesel-hvo-litres",
      "label": "Bioenergy - Biofuel - Biodiesel HVO",
      "publisher": "DEFRA",
      "year": 2026,
      "region": "UK",
      "scope": "Scope 1",
      "category": "Bioenergy",
      "subcategory": "Biofuel",
      "activity": "Biodiesel HVO",
      "detail": null,
      "unit": "litres",
      "kind": "emission",
      "value": 0.03558,
      "output_unit": "kg CO2e",
      "gases": [
        "CO2e"
      ]
    },
    {
      "slug": "bioenergy-biofuel-biodiesel-me-litres",
      "label": "Bioenergy - Biofuel - Biodiesel ME",
…

Show full response

{
  "total": 23,
  "page": 1,
  "limit": 2,
  "count": 2,
  "results": [
    {
      "slug": "bioenergy-biofuel-biodiesel-hvo-litres",
      "label": "Bioenergy - Biofuel - Biodiesel HVO",
      "publisher": "DEFRA",
      "year": 2026,
      "region": "UK",
      "scope": "Scope 1",
      "category": "Bioenergy",
      "subcategory": "Biofuel",
      "activity": "Biodiesel HVO",
      "detail": null,
      "unit": "litres",
      "kind": "emission",
      "value": 0.03558,
      "output_unit": "kg CO2e",
      "gases": [
        "CO2e"
      ]
    },
    {
      "slug": "bioenergy-biofuel-biodiesel-me-litres",
      "label": "Bioenergy - Biofuel - Biodiesel ME",
      "publisher": "DEFRA",
      "year": 2026,
      "region": "UK",
      "scope": "Scope 1",
      "category": "Bioenergy",
      "subcategory": "Biofuel",
      "activity": "Biodiesel ME",
      "detail": null,
      "unit": "litres",
      "kind": "emission",
      "value": 0.16751,
      "output_unit": "kg CO2e",
      "gases": [
        "CO2e"
      ]
    }
  ]
}

GETRandom Factor

https://api-emission-factors.dataandapis.com/v1/factors/random

Query parameters

Parameter	Example
amount	1	Optional

Example request

curl "https://api-emission-factors.dataandapis.com/v1/factors/random?amount=1" \
  -H "X-Api-Key: YOUR_API_KEY"

Example response

{
  "count": 1,
  "results": [
    {
      "slug": "wtt-delivery-vehs-and-freight-wtt-vans-class-iii-1-74-to-3-5-tonnes-petrol-tonne-km",
      "label": "WTT- delivery vehs & freight - WTT- vans - Class III (1.74 to 3.5 tonnes) (Petrol)",
      "publisher": "DEFRA",
      "year": 2026,
      "region": "UK",
      "scope": "Scope 3",
      "category": "WTT- delivery vehs & freight",
      "subcategory": "WTT- vans",
      "activity": "Class III (1.74 to 3.5 tonnes)",
      "detail": null,
      "unit": "tonne.km",
      "kind": "emission",
      "value": 0.24164,
      "output_unit": "kg CO2e",
      "gases": [
        "CO2e"
      ]
    }
  ]
}

GETSource Freshness

https://api-emission-factors.dataandapis.com/v1/factors/updates

Query parameters

Parameter	Example
limit	25	Optional
status	revised	Optional

Example request

curl "https://api-emission-factors.dataandapis.com/v1/factors/updates?limit=25&status=revised" \
  -H "X-Api-Key: YOUR_API_KEY"

Example response

{
  "last_checked": "2026-08-27 13:36:52",
  "editions_needing_reseed": 0,
  "count": 3,
  "checks": [
    {
      "checked_at": "2026-08-27 13:36:52",
      "publisher": "EPA",
      "edition_year": 2024,
      "status": "not-tracked",
      "set_slug": null,
      "seeded_file_url": null,
      "discovered_file_url": "https://www.epa.gov/system/files/documents/2024-02/ghg-emission-factors-hub-2024.xlsx",
      "discovered_published_at": null,
      "detail": null
    },
    {
      "checked_at": "2026-08-27 13:36:52",
      "publisher": "EPA",
      "edition_year": 2025,
      "status": "current",
      "set_slug": "epa-hub-2025",
      "seeded_file_url": "https://www.epa.gov/system/files/other-files/2025-01/ghg-emission-factors-hub-2025.xlsx",
      "discovered_file_url": "https://www.epa.gov/system/files/other-files/2025-01/ghg-emission-factors-hub-2025.xlsx",
      "discovered_published_at": null,
      "detail": null
    },
    {
…

Show full response

{
  "last_checked": "2026-08-27 13:36:52",
  "editions_needing_reseed": 0,
  "count": 3,
  "checks": [
    {
      "checked_at": "2026-08-27 13:36:52",
      "publisher": "EPA",
      "edition_year": 2024,
      "status": "not-tracked",
      "set_slug": null,
      "seeded_file_url": null,
      "discovered_file_url": "https://www.epa.gov/system/files/documents/2024-02/ghg-emission-factors-hub-2024.xlsx",
      "discovered_published_at": null,
      "detail": null
    },
    {
      "checked_at": "2026-08-27 13:36:52",
      "publisher": "EPA",
      "edition_year": 2025,
      "status": "current",
      "set_slug": "epa-hub-2025",
      "seeded_file_url": "https://www.epa.gov/system/files/other-files/2025-01/ghg-emission-factors-hub-2025.xlsx",
      "discovered_file_url": "https://www.epa.gov/system/files/other-files/2025-01/ghg-emission-factors-hub-2025.xlsx",
      "discovered_published_at": null,
      "detail": null
    },
    {
      "checked_at": "2026-08-27 13:36:52",
      "publisher": "DEFRA",
      "edition_year": 2027,
      "status": "unavailable",
      "set_slug": null,
      "seeded_file_url": null,
      "discovered_file_url": null,
      "discovered_published_at": null,
      "detail": "no gov.uk publication for 2027"
    }
  ]
}

Where the data comes from

Source: UK DEFRA/DESNZ greenhouse gas conversion factors (2023 to 2026 editions) and the US EPA GHG Emission Factors Hub.
Freshness: New editions added as published, about once a year per source; prior editions retained.

One install. Every endpoint.

No proprietary SDKs needed. Any HTTP client works. Pick your language and paste.

3languages

10endpoints

RESTarchitecture

1key for all APIs

Fully typed responses — auto-completion in your IDE
Tracks the API in lockstep — new endpoints land same day
One key works across 125+ APIs on the platform

import axios from 'axios';

const { data } = await axios.get(
  'https://api-emission-factors.dataandapis.com/v1/calculate',
  { headers: { 'X-Api-Key': process.env.API_KEY } }
);

Emission Factors API · X-Api-Key

Explore the endpoints

Browse request parameters and inspect live example responses.

Available Endpoints

Request Parameters

API URL

Headers

X-Api-Key

Query Parameters

factor(Required)

publisher(Optional)

quantity(Required)

year(Optional)

Target:

Client:

import axios from 'axios';

const url = 'https://api-emission-factors.dataandapis.com/v1/calculate';
const { data } = await axios.get(url, {
  headers: { 'X-Api-Key': 'YOUR_API_KEY' }
});