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Small Sites Metric Calculation Tool

Here to help: If you need assistance filling out the Small Sites Metric Calculation Tool please email for a quotation phone numbers are at top of page if you prefer.

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Designed for smaller development projects in England where the biodiversity impacts are less complex and extensive. Simplifies the Biodiversity Net Gain (BNG) assessment process, making it more accessible to smaller developers and landowners.

Key Features:

Streamlined assessment: It focuses on a select range of habitat types and biodiversity features, reducing the amount of data required compared to the full Biodiversity Metric. User-friendly interface: It's typically available as a spreadsheet-based tool, making it relatively easy to use and understand. Tailored guidance: It includes specific guidance on how to apply the tool for different types of small sites.


Habitat Mapping:

Users map the existing habitats on the development site, using standardized habitat codes and descriptions.

Impact Assessment:

The tool calculates the biodiversity units lost due to the proposed development, based on the area and quality of affected habitats.

Habitat Creation and Enhancement:

Users input details of planned habitat creation or enhancement measures, such as planting trees or restoring ponds.

Net Gain Calculation:

The tool automatically calculates the overall biodiversity units gained or lost, factoring in both losses and gains.


It generates a report summarizing the assessment results, including the net gain or loss and proposed mitigation measures.

Availability and Use:

The Small Sites Metric Calculation Tool, as well as its user guide and supplementary materials, can be freely accessed and downloaded from the Natural England website: https://publications.naturalengland.org.uk/publication/6047259574927360 It's intended for use by qualified ecologists or professionals with appropriate expertise in biodiversity assessment and BNG.

Additional Considerations:

It may not be suitable for sites with highly sensitive habitats or protected species. For those cases, the full Biodiversity Metric may be required for a more comprehensive assessment. It's important to consult with relevant authorities and guidelines to ensure compliance with local BNG requirements.