As biodiversity net gain (BNG) becomes a mandatory part of the planning process across England, developers are increasingly asking: how much do BNG unit costs?
It’s a fair question—and an important one. If you’re preparing a planning application under the Environment Act 2021, you’ve probably realised that delivering a 10% gain in biodiversity can mean off-site units, which come with their own price tag. But the cost of BNG units can vary significantly depending on a range of factors—from location and habitat type to supply and demand in the area.
In this comprehensive guide, we at The BNG Guy will walk you through the key pricing factors, what to expect when budgeting for BNG units, and how to secure the best value while meeting your planning obligations. Whether you’re a seasoned developer or new to the BNG process, this article is your go-to resource.
What Are BNG Units?
BNG units are a way of quantifying biodiversity improvements. One BNG unit represents a measurable uplift in biodiversity, calculated using Natural England’s Biodiversity Metric. Under the rules introduced by the Environment Act, developers must show that their project will result in a 10% net gain in biodiversity.
There are three types of BNG units:
- Habitat Units – General terrestrial habitats like grasslands or woodlands.
- Hedgerow Units – For linear features such as native hedgerows.
- River Units – For watercourses and associated riparian habitats.
Understanding BNG Units and Their Costs
BNG units, or Biodiversity Net Gain units, play a crucial role in promoting sustainability and ecological responsibility in development projects. These units quantify the measurable biodiversity enhancements that developers are required to achieve as part of their planning permissions. The importance of BNG units is anchored in the UK government’s commitment to enhancing biodiversity and ensuring that new developments have a beneficial impact on the natural environment.
The calculation of BNG units involves assessing the biodiversity value of a specific site before development begins and comparing it to the biodiversity value after development is completed. This process ensures that any loss in biodiversity due to construction activities is mitigated through enhancements that contribute positively to local ecosystems.
Understanding the costs associated with BNG units is essential for developers and investors alike. These costs can vary widely based on factors such as the location of the project, the current biodiversity baseline, and the specific enhancements required to achieve compliance with biodiversity regulations. By investing in BNG units, developers not only contribute to ecological sustainability but also enhance their project’s marketability and compliance with environmental standards, making it a worthwhile consideration in the planning process.
So, How Much Do BNG Units Cost?
Let’s get to the point. As of 2025, the cost of BNG units in England generally falls within the following ranges:
| BNG Unit Type | Low-End Cost (per unit) | High-End Cost (per unit) |
|---|---|---|
| Habitat Units | £20,000 | £35,000+ |
| Hedgerow Units | £30,000 | £45,000+ |
| River Units | £40,000 | £100,000+ |
But before you plug these numbers into your development appraisal, remember: these are just averages. The true price of BNG units is shaped by a mix of supply and demand, habitat scarcity, geographic location, and the delivery mechanism—whether it’s a private landowner, local authority, or government scheme.
Estimating BNG Unit Costs
To accurately estimate BNG unit costs, developers should conduct a thorough assessment of their project’s specific biodiversity needs and goals. Engaging with local biodiversity offset providers can offer valuable insights into current market rates and the types of habitats available for offsetting. Additionally, it is crucial to understand the metrics used to quantify biodiversity gain—such as the Defra Biodiversity Metric—which can assist in determining the number of units required for compliance with local regulations and to achieve meaningful biodiversity outcomes.
Comprehensive Budgeting for BNG Units
When budgeting for BNG (Biodiversity Net Gain) units, it’s essential to consider not only the initial purchase price but also a variety of associated costs that can impact your overall expenditure. Understanding these costs can help you create a more accurate and effective budget. The key expenses to account for include:
- Assessment Costs: Initial assessments are vital for determining the biodiversity values of the area. These assessments often require expert consultancy, which can add to your overall budget. Investing in thorough assessments ensures you make informed decisions about biodiversity enhancements.
- Implementation Costs: Should you decide to create or enhance habitats on-site, these implementation costs must be carefully factored into your budget. This can include labour, materials, and any ecological technology that may be necessary for effective habitat creation.
- Monitoring and Maintenance: Ongoing management of biodiversity units is crucial for ensuring their long-term effectiveness. This may involve regular monitoring, maintenance activities, and potential additional expenditures to address unforeseen issues, all of which should be anticipated in your financial planning.
Comparing BNG Unit Costs vs. Government Credits
Example:
- Shortfall: 4 habitat units
- Government cost: 4 x £42,000 = £168,000
- Private bank cost: 4 x £25,000 = £100,000
Potential saving: £68,000
Real-World Examples
Urban Residential Development – Birmingham
- Requirement: 5 habitat units
- Local unit cost: £32,000/unit
- Saved over £60,000 by reducing off-site needs to 3 units
Rural Commercial Site – Cannock Chase
- Requirement: 10 habitat units
- Cost: £17,500/unit via local landowner
- Total: £175,000 with full compliance
Key Factors That Influence BNG Unit Prices
1. Location, Location, Location
BNG units are more expensive in areas where biodiversity is under pressure or where land is scarce. For example, developers working in densely built-up urban areas like London or Manchester may find it harder (and more expensive) to source units locally.
2. Habitat Type and Distinctiveness
High-distinctiveness habitats such as ancient woodland or lowland meadows are far more valuable than low-distinctiveness habitats like modified grassland.
Here’s a rough breakdown:
- Low distinctiveness: £10,000–£15,000/unit
- Medium distinctiveness: £20,000–£25,000/unit
- High distinctiveness: £30,000–£35,000+/unit
3. Availability of Local Supply
If your development is in an area with multiple habitat banks already delivering biodiversity units, competition helps keep prices reasonable.
4. Time Sensitivity
Got a tight planning deadline? You may have to buy from the first provider with available credits, regardless of cost. Planning ahead gives you more negotiating power and choice.
5. Delivery Model
BNG units are sold through various channels:
- Private Habitat Banks – Often competitive but may have a limited geographic scope.
- Local Planning Authorities – Some councils offer their own units but tend to price them conservatively.
- Government’s Statutory Credit Scheme – This is a last-resort option and is deliberately priced high:
- Habitat units: £42,000 each
- Hedgerow units: £650 each
- River units: £110,000 each
Additional Costs to Consider
When calculating the real cost of BNG units, it’s not just about the headline price. You’ll also need to consider:
- Legal agreements (s106 or conservation covenants)
- Monitoring and reporting (usually over 30 years)
- Ecological consultancy fees
- Brokerage or admin costs
How to Get the Best Value for Your Project
1. Start Early
Talk to your ecologist and local authority as soon as possible. Early action gives you more control over costs.
2. Work With a Specialist (Like Us!)
At The BNG Guy, we specialise in helping developers find cost-effective, compliant solutions.
3. Consider On-Site First
Sometimes, small habitat enhancements can help reduce the need for off-site units.
4. Explore Habitat Banking Options
We work directly with habitat banks across the country and can offer competitive access to available units.
5. Plan for 30 Years
Make sure your chosen provider has solid long-term maintenance and monitoring plans.
Frequently Asked Questions
Q: What is the biodiversity net gain requirement for developers?
A: The biodiversity net gain (BNG) requirement for developers is a statutory obligation introduced under the Environment Act 2021, which mandates that new developments achieve at least a 10% net gain in biodiversity using the statutory biodiversity metric.
Q: How can developers buy biodiversity credits?
A: Developers can buy biodiversity credits from landowners or land managers who have created off-site biodiversity units. These units can be purchased to meet the BNG requirement when on-site improvements are insufficient.
Q: What are off-site biodiversity units?
A: Off-site biodiversity units refer to biodiversity credits generated on different sites than the development site. They are used by developers to compensate for any biodiversity loss caused by their projects.
Q: How do local planning authorities assess biodiversity net gain?
A: Local planning authorities assess biodiversity net gain using the statutory biodiversity metric, which evaluates the biodiversity value of the development site compared to the baseline conditions and the proposed enhancements.
Q: What is the role of Natural England in the biodiversity credits system?
A: Natural England oversees the implementation of biodiversity net gain regulations and provides guidance on the statutory biodiversity metric, ensuring that biodiversity credits are allocated and sold in compliance with the law.
Q: What is the biodiversity gain site register?
A: The biodiversity gain site register is an official record managed by Natural England, documenting all sites that contribute biodiversity credits, making it easier for developers to find and purchase off-site biodiversity units.
Q: What are the benefits of selling biodiversity units for land managers?
A: Selling biodiversity units allows land managers to generate income while contributing to nature recovery efforts. It also helps support the biodiversity net gain goals of developers, fostering a collaborative approach to conservation.
Q: How long do biodiversity credits last?
A: Biodiversity credits are typically required to be maintained for at least 30 years to ensure that the biodiversity gains are sustained over the long term, aligning with the BNG requirements outlined in the regulations.
Q: What happens if a development site cannot achieve the required biodiversity net gain?
A: If a development site cannot achieve the required biodiversity net gain, the developer must purchase off-site biodiversity units or credits to compensate for the shortfall, ensuring compliance with the mandatory BNG regulations.
Q: What is the biodiversity net gain (BNG) requirement for developers?
A: The biodiversity net gain (BNG) requirement mandates that developers must ensure a minimum of 10% increase in biodiversity on their development sites compared to pre-development levels, as outlined in the Environment Act 2021. This requirement is set to become mandatory for most developments in England from April 2024.
Q: How do biodiversity credits work in relation to off-site biodiversity units?
A: Biodiversity credits are a mechanism that allows developers to achieve their biodiversity net gain (BNG) requirement by purchasing off-site biodiversity units from landowners or land managers who have enhanced or restored habitats. This helps to balance the ecological impact of development by supporting conservation efforts elsewhere.
Q: What is the role of the biodiversity metric in calculating biodiversity units?
A: The statutory biodiversity metric, developed by Natural England, is a tool used to quantify biodiversity units based on habitat type, condition, and area. This metric helps developers assess their current biodiversity levels and determine the number of biodiversity units required to meet their BNG requirement.
Q: Can small development sites also be subject to mandatory biodiversity net gain regulations?
A: Yes, small development sites are also subject to the mandatory biodiversity net gain regulations, which will apply to most projects from April 2024. However, there may be specific exemptions for very small sites or certain types of developments, which will be detailed in local planning authorities’ guidelines.
Q: What options do developers have if they cannot achieve biodiversity net gain on-site?
A: If on-site biodiversity net gain cannot be achieved, developers may opt to buy off-site biodiversity units from landowners or land managers. This involves purchasing biodiversity credits that contribute to habitat enhancement or restoration projects elsewhere, thus fulfilling their statutory BNG requirement.
Q: How long must biodiversity enhancements be maintained to satisfy BNG requirements?
A: Biodiversity enhancements must be maintained for at least 30 years to comply with biodiversity net gain requirements. This long-term commitment ensures that the ecological benefits gained from habitat restoration are sustained over time.
Q: What is the biodiversity gain site register, and how does it function?
A: The biodiversity gain site register is an official record maintained by local planning authorities that documents sites where biodiversity net gain has been achieved. It allows developers and landowners to track biodiversity credits and facilitates the trading of biodiversity units to support nature recovery across England.
Q: How can landowners or land managers sell biodiversity units?
A: Landowners or land managers can sell biodiversity units by enhancing their land to improve its ecological value and then registering these units for sale. The biodiversity credits can then be purchased by developers needing to meet their biodiversity net gain obligations, creating a financial incentive for conservation efforts.
The Importance of BNG in Development
Understanding the costs associated with BNG units is crucial for developers, not only to meet regulatory requirements but also to contribute positively to the environment. Biodiversity net gain represents a shift in how development interacts with nature, promoting sustainable practices that benefit both ecosystems and communities.
As developers embrace BNG principles, they not only comply with legislation but also enhance their reputation among stakeholders and the community. Projects that incorporate biodiversity considerations can lead to improved public perception, potential marketing advantages, and long-term sustainability.
Conclusion
BNG units play a crucial role in the planning process for various projects, and it’s important to know that they can be cost-effective. By gaining a deeper understanding of the factors that influence BNG unit costs, you can navigate your budget more effectively. Collaborating with a reliable partner like The BNG Guy will empower you to make informed decisions that align with your development objectives while being mindful of environmental impacts.
So, the next time someone asks you “how much do BNG units cost?”, you’ll be well-equipped to provide a knowledgeable response and guide them to the right resources for assistance.