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Guidance

Statutory biodiversity metric tools and guides

Tools and guides for measuring the biodiversity value of habitat for biodiversity net gain (BNG).

Updates to this page

From:
Department for Environment, Food & Rural Affairs
Published:
29 November 2023
Last updated:
2 June 2026
Show all updates

  1. Minor updates to the metric user guide to provide further clarity on the spatial risk multiplier, rule 4, and combining habitat parcels. Updated the user guide to also apply to nationally significant infrastructure projects (NSIPs). Biodiversity net gain will be mandatory for NSIPs from 2 November 2026. Full details of the updates are listed in the document ‘Statutory biodiversity metric tools and guides: version history’.

  2. We've made routine minor updates to the statutory metric documents to fix minor issues, provide extra clarification and more detailed information on watercourse module metric inputs. These updates do not affect biodiversity unit outputs and full details of the updates are listed in the document ‘Statutory biodiversity metric tools and guides: version history’. The updates relate to BNG as it currently applies (July 2025), and any potential future changes resulting from the outcome of the current BNG consultation will be considered after the government response to the consultation is published.

  3. Companies who use data from the metric calculation tools for their own BNG software can now sign up to be notified in advance of any changes to the tools.

  4. Updated to confirm that you can use any version, including previously published versions, of the statutory metric tools for BNG calculations.

  5. Replaced the incorrect small sites metric calculation tool with a corrected version.

  6. Minor updates within the metric tools and user guides. A summary of the changes is outlined in the version history at the start of each document.

  7. Updated box at top of page to state that biodiversity net gain (BNG) is mandatory from 12 February 2024 and removed the 'draft guidance' label. Added information on transferring data from 4.0 to the statutory biodiversity metric. Updated user guides to provide further detail and clarifications, including the assessment of strategic significance and when to record individual trees. Updated calculation tools to correct some labelling errors, minor formula errors and expand width of columns. Updated condition assessments to remove redundant references, reflect the inclusion of sea buckthorn as an invasive coastal species and align the assessment of individual trees to the clarified approach in the user guide.

  8. Amended the statutory biodiversity metric calculation tool to fix an error in the irreplaceable habitats dropdown and minor changes to the working of the tool such as ensuring the rows auto populate correctly and cells adjust their height so error messages can be read.

  9. First published.

Applies to England

Documents

Statutory biodiversity metric: user guide

PDF, 2.18 MB, 89 pages

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Statutory biodiversity metric calculation tool (macro enabled)

4.12 MB

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Statutory biodiversity metric calculation tool (macro disabled)

MS Excel Spreadsheet, 4.05 MB

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Small sites metric (statutory biodiversity metric): user guide

PDF, 1.04 MB, 63 pages

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Small sites metric (statutory biodiversity metric): calculation tool

877 KB

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Statutory biodiversity metric condition assessments

MS Excel Spreadsheet, 379 KB

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Statutory biodiversity metric tools and guides: version history

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Transferring data from 4.0 to the statutory biodiversity metric calculation tool

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Details

This page applies to:

  • developments that need planning permission
  • nationally significant infrastructure projects (NSIPs), from 2 November 2026

You can use any version of the statutory metric tools for BNG calculations. Updates will not affect biodiversity unit outputs. Details of any updates will be listed in the version history of each document.

If you are a company who uses data from the metric calculation tools for your own BNG software, you can sign up to be notified in advance of any changes to the tools, to ensure you are able to incorporate them into your software.

Sign up here if you want to be notified of these updates.

The statutory biodiversity metric tool and user guide

The tool allows the calculation of biodiversity value for the purpose of BNG for developments. The user guide has the information needed to use the statutory biodiversity metric tool.

You can read more about calculating biodiversity value for the purpose of BNG (this additional guidance only applies to developments that need planning permission).

Statutory biodiversity metric condition assessments

These provide condition assessment criteria for all relevant metric habitats. This allows a standard approach to collecting and inputting the correct data for habitat condition.  

Small sites statutory biodiversity metric calculation tool and user guide 

The small sites biodiversity metric tool allows the calculation of biodiversity value for the purpose of BNG for small developments.  The user guide provides all the information needed to use the small sites biodiversity metric tool. 

Moving from older versions of the biodiversity metric

‘Transferring data from 4.0 to the statutory biodiversity metric calculation tool’ explains how to copy over from previous versions of the biodiversity metric. There is information on the changes since 4.0 and more tools, case studies and technical detail available from Natural England.

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