What is a BNG assessment in the UK?

A Biodiversity Net Gain (BNG) assessment is a mandatory calculation for most UK planning applications since February 2024, under the Environment Act 2021. It measures the biodiversity value of a development site before and after construction using the Statutory Biodiversity Metric 4.0, and the developer must deliver at least a 10% uplift in biodiversity units. BioNetGain Pro produces a legally compliant BNG report in under 30 minutes.

How much does a biodiversity net gain report cost in the UK?

A BioNetGain Pro BNG report starts at £95 for sites under 0.1 hectares (micro sites). Pricing scales with site area: small sites (0.1–0.5 ha) from £195, minor developments (0.5–1 ha) from £295, and major developments (1+ ha) from £495. This is 70–90% cheaper than a traditional ecological consultancy, which typically charges £2,000–£8,000 and takes 5–10 working days.

Is BioNetGain Pro BNG report legally compliant?

Yes. Every BioNetGain Pro report uses the DEFRA Statutory Biodiversity Metric 4.0, produces a Biodiversity Gain Plan (BGP) in the Natural England-accepted format, and includes a 30-year Habitat Management and Monitoring Plan (HMMP) alongside Section 106 or Conservation Covenant legal mechanism drafting. Reports are accepted by all 317 UK Local Planning Authorities.

Which development sites need a BNG assessment?

Since 12 February 2024 most major developments in England require a 10% BNG uplift. Since 2 April 2024 small sites (fewer than 10 dwellings, or under 0.5 hectares) also require BNG. Nationally Significant Infrastructure Projects (NSIPs) come into scope in late 2025. Exemptions include householder applications, change-of-use without development, and de minimis sites under 25 m² of habitat impact.

How does the BNG calculator work?

The BioNetGain Pro BNG calculator uses the Statutory Biodiversity Metric 4.0 formula: biodiversity units = area (ha) × habitat distinctiveness × condition × strategic significance × spatial risk × temporal risk. We automate the baseline assessment with AI-processed satellite imagery via our partnership with Gentian True Sight, then apply the developer's planned scenario to calculate post-development units and the 10% gain target.

How long does a BNG report take?

A BioNetGain Pro report is delivered within 30 minutes of boundary submission. This compares with 5–10 working days for a traditional ecological consultancy. The speed comes from our AI-driven baseline habitat mapping and the automated Metric 4.0 calculation engine.

Do I need a PEA as well as a BNG report?

In most cases, yes. A Preliminary Ecological Appraisal (PEA) covers protected species, designated sites, and construction impacts — it is a separate statutory requirement from BNG. BioNetGain Pro handles the BNG compliance layer: metric calculation, HMMP, submission pack, trading rules, off-site options, and S106 drafts. Your ecologist handles the PEA. Together, the two documents satisfy the complete ecological requirements for your planning application.

Why do LPAs reject BNG reports?

The most common reasons LPAs reject BNG submissions are: no Habitat Management and Monitoring Plan (HMMP), no committed pathway to achieving 10% net gain (just a generic statement that options exist), missing trading rules analysis, no costed off-site compensation comparison, and no mitigation hierarchy narrative. BioNetGain Pro includes all of these as standard in every submission pack, giving the LPA confidence that the biodiversity gain condition is capable of being discharged before determination.

What Is Biodiversity Net Gain? Complete Developer Guide 2026

What Is Biodiversity Net Gain?

Biodiversity Net Gain (BNG) is a legal requirement under the Environment Act 2021 that ensures developments deliver at least a 10% increase in biodiversity compared to the pre-development baseline. It became mandatory for major developments on 12 February 2024 and for small sites on 2 April 2024.

Who Does BNG Apply To?

Almost every planning application in England that involves habitat disturbance now requires a BNG assessment. This includes residential developments, commercial schemes, infrastructure projects, and changes of use. Only a narrow set of exemptions exist — primarily for householder applications and self-build plots under certain conditions.

How Is BNG Measured?

BNG is measured using the Statutory Biodiversity Metric 4.0, published by DEFRA. The metric calculates biodiversity units based on habitat type, area, condition, and strategic significance. Your development must demonstrate that the post-development site — including any off-site compensation — delivers at least 10% more biodiversity units than the baseline.

What Documents Do You Need?

To satisfy BNG requirements, you typically need:

A BNG Compliance Report demonstrating the 10% net gain calculation
A Habitat Management and Monitoring Plan (HMMP) compliant with Natural England's JP058 template
A completed DEFRA Statutory Metric 4.0 spreadsheet
A Biodiversity Gain Plan for submission with your planning application

How BioNetGain Pro Helps

BioNetGain Pro generates your complete BNG submission pack — Compliance Report, HMMP, DEFRA export, and monitoring dashboard — in under one hour, from £295. An ecology consultant typically charges £3,000 to £8,000 for the same documents and takes 4 to 8 weeks.

What Is Biodiversity Net Gain? A Complete Guide for Developers

What Is Biodiversity Net Gain?

Who Does BNG Apply To?

How Is BNG Measured?

What Documents Do You Need?

How BioNetGain Pro Helps

Need help with BNG compliance?

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