Statutory biodiversity metric tools and guides

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.

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

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

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.

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box at top of page to state that biodiversity net gain (BNG) is mandatory from 12 February 2024 and removed the 'draft guidance' label.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.

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.

First published.