BNG User Guide Explained
The BNG user guide is the essential companion to the statutory Biodiversity Metric 4.0, helping developers, ecologists, and planning consultants understand exactly how to measure and deliver Biodiversity Net Gain (BNG).
Published by DEFRA and Natural England, the user guides explain how to complete calculations, assess habitats, and comply with the Environment Act 2021. This page summarises what the official BNG user guides include, how they differ from earlier versions, and how ACP Consultants applies them to real projects. We also provide links to download the latest official documents and a practical checklist for BNG compliance.
- Our Biodiversity Net Gain (BNG) Services in England:
- BNG baseline habitat surveys (Metric 4.0 compliant)
- Biodiversity unit calculations & deficit analysis
- Habitat creation, enhancement & on-site mitigation design
- Biodiversity Gain Plans (BGP) for planning submission
- Off-site BNG strategy & unit sourcing advice
- Habitat Management & Monitoring Plans (HMMP)
- Pre-application BNG feasibility & risk reviews
- Planning condition discharge & post-consent support
We follow a simple, transparent process to ensure your project runs smoothly from the very first contact to the final report. Our approach is designed to provide you with clarity at every step, so you’re fully informed and confident in moving forward.
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Step 1: Request a Quote
Fill out our quick quote form or call us, and our team will provide a free, no-obligation quote, outlining the services tailored to your needs.
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Step 2: Confirm Your Booking
Once you approve the quote, simply return the booking form. We’ll schedule your survey and ensure all the details are taken care of.
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Step 3: Receive Your Report
After your survey is completed and payment is received, we’ll promptly issue your survey report, ensuring you get the results as quickly as possible.
In the past year, we’ve delivered over 750+ audit-ready reports supporting 400+ projects for developers, planners, and architects nationwide. We put quality over quantity and build lasting relationships based on trust, ensuring your planning applications are backed by robust evidence and delivered on time.
What Is the BNG User Guide?
The BNG user guide is a technical document that supports the statutory Biodiversity Metric, the tool used to calculate habitat value before and after development. Its purpose is to ensure that all practitioners from ecological consultants to planning officers interpret and apply the metric consistently.
The guide explains how to classify habitats, score condition, and determine distinctiveness in line with UKHab standards. It also provides instructions for completing the BNG calculator and recording habitat changes accurately. In essence, the BNG user guide ensures that every Biodiversity Net Gain calculation across England follows the same nationally approved approach.
Who Publishes It and Why
The DEFRA BNG user guide and related technical papers are produced jointly by the Department for Environment, Food & Rural Affairs (DEFRA) and Natural England, with expert input from the CIEEM and other ecological organisations.
DEFRA and Natural England Roles
- DEFRA sets national BNG policy under the Environment Act 2021, defining statutory requirements and developing the metric.
- Natural England manages and maintains the technical documentation such as JP058 and associated spreadsheets and updates them when new ecological evidence or policy changes emerge.
The shared goal is consistency. By following the Biodiversity Metric 4.0 user guide, developers and consultants can demonstrate measurable BNG outcomes that align with planning regulations and local validation requirements.
Overview of the DEFRA BNG Metric 4.0 User Guide
The DEFRA Biodiversity Metric 4.0 User Guide (JP058) is the primary technical document supporting the statutory Biodiversity Net Gain (BNG) framework in England. It provides detailed, step-by-step guidance on how to apply the Biodiversity Metric 4.0 in accordance with the Environment Act 2021, ensuring that biodiversity value is measured consistently across all developments. The guide explains how to classify habitats using UKHab standards, assess habitat condition through structured field surveys, and assign distinctiveness scores to calculate baseline biodiversity units. It also sets out how to measure post-development habitat value and determine whether the required minimum 10% Biodiversity Net Gain has been achieved.
A key feature of the DEFRA BNG user guide is its structured approach to risk adjustment. Temporal risk multipliers account for the time required for habitats to establish, while spatial risk multipliers address the implications of delivering biodiversity enhancements off-site. The guide also includes worked examples, helping practitioners understand how to apply the metric in real-world scenarios such as brownfield redevelopment, greenfield sites, and linear habitats.
By following the DEFRA Biodiversity Metric 4.0 User Guide, ecological consultants, developers, and planning authorities can ensure that BNG calculations are transparent, repeatable, and compliant with national policy. It forms the foundation of all statutory BNG assessments and is essential for preparing planning submissions that meet local authority validation requirements.
Updates from Previous Metric Versions
The transition to Biodiversity Metric 4.0 marks a significant evolution from earlier DEFRA metric versions, particularly in its role as a statutory tool under the Environment Act 2021. Previous iterations, such as Metric 3.0, were primarily used as best-practice guidance, whereas Metric 4.0 is now mandatory for applicable developments in England. This shift has required greater clarity, consistency, and robustness in the BNG user guide.
One of the most notable updates is the refinement of habitat condition assessment criteria. The revised condition sheets provide clearer, more measurable indicators, reducing subjectivity and improving consistency between ecological consultants. In addition, habitat distinctiveness categories have been updated to better reflect ecological value, ensuring that biodiversity units more accurately represent real-world habitat quality.
Metric 4.0 also integrates separate modules—such as river, hedgerow, and area-based habitats—into a unified framework, simplifying the calculation process and reducing duplication. The DEFRA BNG user guide now includes more detailed guidance on temporary impacts, phased developments, and habitat creation timelines, helping practitioners address complex project scenarios.
Importantly, the metric has been aligned with the Small Sites Metric, ensuring compatibility across different development scales. These updates collectively improve usability, reduce ambiguity, and strengthen the defensibility of BNG calculations. As a result, Biodiversity Metric 4.0 provides a more reliable and consistent basis for demonstrating Biodiversity Net Gain in planning applications.
Natural England’s Technical Guidance
Natural England’s technical guidance plays a critical role in supporting the DEFRA Biodiversity Metric 4.0 User Guide, providing additional detail, clarification, and scientific context for practitioners applying Biodiversity Net Gain (BNG). Key documents such as JP058 (Statutory Biodiversity Metric User Guide) and JP039 (Biodiversity Metric supporting information) expand on the methodology, explaining the ecological principles and evidence underpinning habitat scoring, condition assessment, and distinctiveness categories.
These guidance documents include standardised condition assessment sheets, which are essential for conducting consistent field surveys. By following these templates, ecologists can ensure that habitat condition is assessed in line with national standards, reducing variability between assessments and improving the reliability of biodiversity unit calculations. Natural England also provides worked examples, technical notes, and periodic updates to address common queries and emerging issues in BNG implementation.
In addition to the core user guide, Natural England publishes supplementary resources such as the Small Sites Metric User Guide, which is tailored to minor developments, and ongoing blog updates that clarify interpretation of policy and technical requirements. These resources are particularly valuable where site-specific complexities arise, such as mixed habitats, phased delivery, or off-site compensation strategies.
Together, DEFRA and Natural England guidance documents form a comprehensive framework for applying the statutory biodiversity metric. They ensure that Biodiversity Net Gain assessments are grounded in robust ecological science, aligned with current policy, and consistently applied across England, supporting both regulatory compliance and best practice in ecological consultancy.
How ACP Applies the BNG User Guides
ACP Consultants applies the DEFRA Biodiversity Metric 4.0 User Guide and Natural England technical guidance through a structured, project-specific methodology designed to deliver accurate and compliant Biodiversity Net Gain (BNG) assessments. Our approach begins with detailed baseline habitat surveys, where habitats are classified using UKHab standards and assessed for condition using official Natural England field criteria. This ensures that all baseline biodiversity units are calculated in accordance with the statutory metric.
Following data collection, the Biodiversity Metric 4.0 is applied to quantify existing biodiversity value and model post-development scenarios. This includes the correct application of distinctiveness scores, condition assessments, and risk multipliers such as temporal and spatial factors. Where necessary, ACP identifies opportunities for on-site habitat enhancement or off-site compensation to achieve the required minimum 10% Biodiversity Net Gain.
Our workflow integrates GIS-based habitat mapping, allowing for precise spatial representation of habitats and clear documentation of proposed changes. All calculations are supported by transparent spreadsheets and aligned directly with the DEFRA BNG user guide, ensuring consistency and traceability throughout the assessment process.
ACP also prepares comprehensive BNG reports, including Biodiversity Net Gain Plans and Habitat Management and Monitoring Plans (HMMPs), which meet local planning authority requirements. By translating complex technical guidance into clear, practical outputs, we help developers, architects, and planning consultants navigate BNG requirements efficiently while maintaining full compliance with statutory guidance.
Ensuring Compliance and Audit Readiness
Ensuring compliance with the DEFRA Biodiversity Metric 4.0 User Guide and Natural England guidance is critical for securing planning approval and demonstrating Biodiversity Net Gain (BNG). ACP Consultants adopts a rigorous, audit-ready approach that embeds transparency and traceability at every stage of the BNG assessment process. Each calculation, assumption, and data input is clearly documented and referenced back to the relevant sections of the BNG user guide, creating a defensible audit trail.
This structured approach is particularly important as local planning authorities increasingly require detailed evidence to support BNG submissions. By maintaining comprehensive datasets, including habitat survey records, condition assessment sheets, GIS mapping outputs, and metric calculation files, ACP ensures that all elements of the assessment can be independently verified. This reduces the risk of delays, queries, or rejection during the planning process.
ACP also monitors updates to DEFRA and Natural England guidance, ensuring that all assessments reflect the most current version of the statutory biodiversity metric. This is essential as BNG guidance continues to evolve, with future updates (such as potential Metric 5.0 revisions) expected to refine methodologies further.
In addition to supporting planning approval, an audit-ready approach provides long-term value. It ensures that post-consent monitoring, reporting, and compliance checks can be undertaken efficiently, with clear reference to the original assessment. By aligning every project with the latest BNG user guide requirements, ACP helps clients minimise regulatory risk and deliver robust, policy-compliant biodiversity outcomes.
Need Help Applying the BNG User Guides to Your Project?
We translate Defra’s Biodiversity Net Gain user guides into clear, project-specific actions helping you apply the correct guidance for baseline surveys, metric calculations and Biodiversity Gain Plan preparation.
Where to Find the Official Guides
You can access the latest BNG user guide and related resources directly from the UK Government and Natural England websites:
- DEFRA – Statutory Biodiversity Metric Tools and Guides (GOV.UK)
- The Statutory Biodiversity Metric: User Guide (JP058, July 2025)
- Small Sites Metric – User Guide (July 2025)
- Biodiversity Metric Supporting Documents (JP039)
- Natural England Publications Catalogue
Always use the most recent versions, as older metrics (3.0 or earlier) are no longer valid for statutory BNG calculations.
BNG Guidance in Context
Understanding how the BNG user guide fits within wider planning policy is crucial. It sits alongside other statutory requirements such as:
- Environment Act 2021, mandating at least 10 % Biodiversity Net Gain.
- National Planning Policy Framework (NPPF), which embeds BNG into sustainable development principles.
- CIEEM and IAQM professional guidance, supporting consistent ecological reporting.
ACP’s consultants integrate these frameworks to ensure that every BNG plan or assessment aligns with the expectations of Natural England and local authorities.
References and Useful Resources
- Defra & Natural England – Biodiversity Metric: Calculate the biodiversity net gain of a project or development
- Lichfield District Council – Biodiversity Net Gain (BNG) Guidance for Planning Applications
- East Devon District Council – How is Biodiversity Net Gain Measured?
- Defra (July 2025) – The Statutory Biodiversity Metric: User Guide
- North Hertfordshire District Council – How to Measure Biodiversity Net Gain
- Chartered Institute of Ecology and Environmental Management (CIEEM) – Biodiversity Net Gain Case Studies & Good Practice
- CIEEM – Biodiversity Net Gain Report and Audit Templates
- UK Statutory Instruments – The Biodiversity Gain Requirements (Exemptions) Regulations 2024
- Natural England – Habitat Management and Monitoring Plan (HMMP) Template (JP058)
- Defra – Biodiversity Gain Plan: Template and Guidance
- Defra – Guidance: Understanding Biodiversity Net Gain
- Natural England – Biodiversity Net Gain: Where to Start
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Frequently Asked Questions
The following FAQs address common questions about the BNG user guide, metric 4.0, and how consultants like ACP interpret and apply the official DEFRA and Natural England resources. These help clarify practical issues and reinforce key search topics often found on Google and GOV.UK.
What is the BNG User Guide?
It is the official instruction manual explaining how to calculate Biodiversity Net Gain using the statutory biodiversity metric. It includes definitions, worked examples, and condition assessment methods.
Who publishes the BNG User Guide?
The Department for Environment, Food & Rural Affairs (DEFRA) and Natural England jointly publish the guides, with updates available through GOV.UK.
Is the DEFRA BNG User Guide mandatory?
Yes. From February 2024, all developments subject to the Environment Act 2021 must use the statutory Biodiversity Metric 4.0 and follow the accompanying user guide.
What’s new in the 2024 version?
The latest update (Metric 4.0) incorporates revised condition assessment sheets, refined habitat distinctiveness categories, and integration with the Small Sites Metric, improving accuracy and consistency.
Where can I download the official BNG User Guide?
It can be downloaded free from GOV.UK under “Statutory Biodiversity Metric tools and guides.” Always verify the document code (JP058 or latest version).
How does ACP Consultants use the guidance?
ACP interprets the BNG metric user guide within ecological assessments, applying it to create BNG plans, calculations, and management strategies that fully comply with statutory requirements.
Does every project need to follow the user guide?
Yes, if the project triggers mandatory BNG under planning law. Even exempt schemes are encouraged to apply the same principles to demonstrate environmental best practice.
What happens if you don’t use it correctly?
Incorrect application of the BNG metric user guide can lead to planning delays, data rejection, or non-compliance with the Environment Act 2021. Local authorities may request revisions or additional surveys.
Is the BNG User Guide free to use?
Yes. Both the DEFRA and Natural England user guides are available free of charge for public and professional use.
How often is the BNG guidance updated?
Typically, major updates occur every one to two years as ecological science advances and policy requirements evolve.
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From understanding the relevant BNG user guides to delivering Defra Metric 4.0 calculations, Biodiversity Gain Plans and validation-ready documents, our ecologists support compliant BNG delivery across England.
- Last Updated:
- September 2026
Disclaimer: Our content is prepared by ACP Consultants’ in-house specialists and is based on current guidance, standards, and best practice in environmental consultancy. While we make every effort to keep information accurate and up to date, it is provided for general guidance only and should not be relied upon as a substitute for professional advice on specific projects. Planning authorities retain final decision-making powers, and requirements may vary between local authorities and over time. ACP Consultants accepts no liability for any loss arising from reliance on this content without obtaining tailored advice for your project.