Carbon footprint measurement standards

To measure a carbon footprint in a credible, comparable way, you need to follow a recognised standard. The main ones are the GHG Protocol and the ISO 14064 family for organisations, ISO 14067 for products, and PAS 2050, now withdrawn. Each applies to a different type of footprint and a different purpose.

Choosing the right standard matters: it determines which emissions are included, how they are calculated, and whether the result can be verified or certified by a third party. Before choosing, it helps to be clear on what a carbon footprint is and how it is calculated.

Comparison of the main standards

GHG Protocol

The GHG Protocol (Greenhouse Gas Protocol) is the most widely used emissions accounting framework in the world. It is developed by the World Resources Institute (WRI) and the World Business Council for Sustainable Development (WBCSD); its Corporate Standard was first published in 2001, and in 2011 the specific scope 3 (Corporate Value Chain) and product standards were added.

Its key contribution is classifying emissions into three scopes (1, 2 and 3), which makes it possible to analyse each source and compare results across companies and sectors. It is the methodological basis underpinning most reporting frameworks and science based targets (SBTi).

ISO 14064

The ISO 14064 standard is the certifiable international standard for quantifying and verifying greenhouse gas emissions. It is compatible with the GHG Protocol and serves companies as well as projects, events or products. It is structured in three parts:

• ISO 14064-1: specifies how to design and compile an organisation's GHG inventory. Its current 2018 version organises emissions into six reporting categories.
• ISO 14064-2: focuses on specific emission reduction or removal projects, and on how to quantify and report those improvements.
• ISO 14064-3: governs verification and validation by an independent body, which lends credibility to the data.

If you want to go deeper, we have a dedicated guide on what ISO 14064 is and what it is for and a comparison of GHG Protocol versus ISO 14064-1.

ISO 14067: product carbon footprint

The ISO 14067 standard is the specific international standard for calculating the product carbon footprint (PCF). It builds on the principles of life cycle assessment (ISO 14040 and ISO 14044) and quantifies the emissions of a good or service across all its stages, from raw materials to end of life.

Other standards

• PAS 2050: a British specification published by BSI in 2008 and updated in 2011, a pioneer in calculating the product footprint by life cycle. BSI withdrew it in 2021, so its role is now filled by ISO 14067. You can see the detail in the glossary on PAS 2050.
• Bilan Carbone: a methodology developed in France (ADEME) to calculate the emissions of organisations and territories, widely used in the French-speaking market.
• ISO 14068-1: a 2023 standard that sets the requirements for declaring carbon neutrality in a verifiable way.

How to choose the right standard

The choice depends on three main factors:

• What you want to measure: the GHG Protocol and ISO 14064 cover an organisation's footprint; ISO 14067 covers a product's.
• What you need it for: if you require external verification or certification (for example, for a public tender or Spain's MITECO registry), it is best to rely on ISO 14064.
• The regulatory context: frameworks such as the EU's CSRD require emissions to be reported using recognised methodologies like those above.

In practice, the GHG Protocol and ISO 14064 are not mutually exclusive: most companies calculate their inventory with the GHG Protocol and verify it against ISO 14064.

Frequently asked questions

What is the difference between the GHG Protocol and ISO 14064?

The GHG Protocol is a very detailed methodological framework for accounting emissions; ISO 14064 is a certifiable standard, more focused on verification. They are compatible and are usually used together.

Is PAS 2050 still in force?

No. BSI withdrew PAS 2050 in 2021. For the product carbon footprint, the reference standard is now ISO 14067.

Which standard does MITECO accept to register a carbon footprint?

Spain's MITECO registry accepts inventories prepared in line with the GHG Protocol or ISO 14064, among other recognised methodologies.

Whatever the standard, the challenge is usually collecting the data and applying the right emission factors. Manglai's carbon footprint solution automates the calculation in line with the GHG Protocol and ISO 14064 and prepares reports ready for verification.