Methodology
How a figure is calculated.
MetricOra follows the GHG Protocol Corporate Standard. This page shows what you can check in every figure, where the factors come from and how the rules are versioned.
Our promises
What holds for every figure.
- 01
Rules that stay put
A calculation run is pinned to one factor library and one methodology version, so the rules behind a figure never change underneath it.
- 02
Every figure traces back
Open any total and follow it to the record, the factor, the formula and the evidence behind it.
- 03
Published figures do not change
A correction creates a new version of the report. The earlier one stays as it was, and the change is logged.
- 04
Uncertainty is shown
Totals carry a range, not only a single number, and anything that needed judgement is listed for the reviewer before publishing.
Verify it yourself
Built for the person who checks it.
- Trace a figure from the published total down to the record, factor and formula
- Every emissions report ships with a CSV of each record, factor and formula used
- An assurance pack for auditors: the calculations, the factors, the evidence index and the audit log, with a checksum list
- An auditor role with read-only access to the figures and the evidence behind them
*Demo data
Factor libraries
Sources and licences.
A calculation run is pinned to one library. For each period, the newest DEFRA set whose year is not after the period's end is suggested.
| Library | Covers | Licence |
|---|---|---|
| DEFRA / DESNZ 2026.1 | UK conversion factors, including heat and steam | Open Government Licence v3.0 |
| DEFRA / DESNZ 2025.2 | UK conversion factors for 2025 periods | Open Government Licence v3.0 |
| US EPA GHG Emission Factors Hub 2025 | US fuels and electricity | US Government work |
| EPA USEEIO 1.3 | Spend factors for 1,016 NAICS-6 industries, 2022 USD | US Government work |
| ADEME Base Carbone 2025 | French and European factors, heat networks, EUR spend by NAF | Licence Ouverte 2.0 |
| Defra UK spend multipliers 2023 | Spend factors for 111 UK SIC groups, 2015 to 2023 | Open Government Licence v3.0 |
Every report and CSV export carries the attribution each licence requires.
Calculation
Four steps for every record.
- 01
Normalise the unit
Each quantity is converted to the unit its factor uses, and the original is kept.
- 02
Select the factor
Your own factors are used first. Otherwise the best match from the run's library is chosen, and the reason is stored with the result.
- 03
Compute CO₂e
Gases use IPCC AR6 100-year warming potentials. The formula is saved with the result.
- 04
Store the result
Calculations are never edited. A new run creates new rows, and the snapshot you publish points at one run.
The judgement calls, written down.
- Headline totals use location-based Scope 2. Market-based is shown beside it and never added.
- Market-based electricity follows the GHG Protocol order, and a certificate is never claimed twice.
- Spend is converted at the exchange rate for the record's date and adjusted for inflation to the factor's price year.
- HVO and biomass carry their biogenic CO₂ beside the inventory, not in it.
- Every total carries an uncertainty range.
Versions
Methodology history.
The version changes only when a rule would change a figure from the same records and library. Published snapshots keep the version they were calculated under. The full account of each change is in the app and the assurance pack.
ghg-protocol-v2026-05
National factor sets for more countries, regional electricity where a site's location is known, and sharper fuel matching.
ghg-protocol-v2026-04
A record the chosen factor set cannot price now uses a clearly labelled alternative, flagged on the result, instead of being left at zero.
ghg-protocol-v2026-03
Gallons are now read according to the record's country.
ghg-protocol-v2026-02
Spend is priced by supplier industry where known, heat and cooling are counted in Scope 2, and inflation adjustment covers more currencies.
ghg-protocol-v2026-01
First version: GHG Protocol Corporate Standard, IPCC AR6 warming potentials, location- and market-based Scope 2 side by side.
Read more
Guides for this
- UK conversion factors 2026
What changed and which set to use for which period.
- Location-based and market-based Scope 2
The two methods, with one office as the example.
- Spend-based Scope 3
Pricing supplier spend with factors you can source.
Check the numbers yourself.
Every report ships with a CSV that lists each record, factor and formula used.