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Curious how nature gets measured for Biodiversity Net Gain? This article unpacks the biodiversity metric—how it works, who uses it, and what it means for landowners looking to restore habitats or sell units.
Biodiversity Net Gain might sound like a noble idea, but the first question most landowners ask is: “How do you actually measure nature?”
Well, the government’s answer is something called the biodiversity metric. It’s the tool that turns hedgerows, meadows, ponds and woodlands into measurable biodiversity units—so developers, planners, and landowners can speak the same language when it comes to protecting and improving habitats.
It’s not magic. But it is technical. So let’s break it down.
The biodiversity metric is a standardised calculator, developed by Natural England, that gives a numerical value to the biodiversity of a given site. It looks at the types of habitats you have, their size, condition, and location—and converts all of that into “biodiversity units”.
These units are what developers must offset or increase through BNG. For example, if a development damages 100 biodiversity units, the law says they must create or enhance 110 units elsewhere to meet the 10% net gain requirement.
And this isn’t just a one-off number. The metric is used throughout the planning process—from baseline assessments to biodiversity gain plans, and to monitor long-term commitments.
It’s all about habitat value—not just how much land there is, but how rich and useful it is for wildlife. The metric accounts for:
When you're proposing new habitats (say, planting woodland or restoring a meadow), the metric also factors in:
All of this helps ensure that one habitat can’t be casually swapped for another. A mature woodland, for example, isn’t the same as a patch of rough grass—and the metric recognises that.
If your land is being developed—or if you’re creating a biodiversity gain site to sell units—you’ll need a qualified ecologist to do the number crunching.
The ecologist surveys the land, inputs data into the statutory metric spreadsheet, and calculates the biodiversity units gained or lost. Local planning authorities will then review the submitted figures as part of the planning process.
For small developments (like self-builds), there’s a simplified version called the Small Sites Metric (SSM), which is easier and quicker to use—but still needs a competent person to complete.
Since February 2024, all planning applications subject to BNG must use the official statutory version of the biodiversity metric. This replaced older versions like Metric 3.1 or 4.0, which were used voluntarily before BNG became law.
So, if you're still working off an old spreadsheet from a previous woodland plan—time for an upgrade. The statutory version is the only one that planning authorities will now accept.
If you're considering selling biodiversity units or restoring habitats for conservation or income, the metric helps you understand what your land is worth in biodiversity terms.
It can also show you how different land-use choices affect that value. For example:
This helps landowners like Thomas make smart, financially sound decisions before investing time, money, or grant funding.
Not really. The rules are strict, and local planning authorities are trained to spot poor-quality submissions. Biodiversity units must be backed by evidence, verified by ecologists, and managed long-term—often under legally binding agreements.
That’s good news. It keeps the system credible and protects landowners who are doing things properly from being undercut by quick-fix schemes.
The biodiversity metric is what makes BNG work. It takes something as complex as “nature” and gives us a clear, consistent way to measure it—whether you’re a developer applying for planning permission, or a landowner looking to create wildlife-rich habitats with long-term value.
Want to understand how many biodiversity units your land could offer? Start with a conversation—and the right metric tool. At AskGrant, we’re here to help you make sense of the numbers, explore your land’s potential, and connect you with trusted experts who know the system inside out.
Whether you're just curious or ready to take the next step, we’re always happy to chat.
Curious how nature gets measured for Biodiversity Net Gain? This article unpacks the biodiversity metric—how it works, who uses it, and what it means for landowners looking to restore habitats or sell units.
Biodiversity Net Gain might sound like a noble idea, but the first question most landowners ask is: “How do you actually measure nature?”
Well, the government’s answer is something called the biodiversity metric. It’s the tool that turns hedgerows, meadows, ponds and woodlands into measurable biodiversity units—so developers, planners, and landowners can speak the same language when it comes to protecting and improving habitats.
It’s not magic. But it is technical. So let’s break it down.
The biodiversity metric is a standardised calculator, developed by Natural England, that gives a numerical value to the biodiversity of a given site. It looks at the types of habitats you have, their size, condition, and location—and converts all of that into “biodiversity units”.
These units are what developers must offset or increase through BNG. For example, if a development damages 100 biodiversity units, the law says they must create or enhance 110 units elsewhere to meet the 10% net gain requirement.
And this isn’t just a one-off number. The metric is used throughout the planning process—from baseline assessments to biodiversity gain plans, and to monitor long-term commitments.
It’s all about habitat value—not just how much land there is, but how rich and useful it is for wildlife. The metric accounts for:
When you're proposing new habitats (say, planting woodland or restoring a meadow), the metric also factors in:
All of this helps ensure that one habitat can’t be casually swapped for another. A mature woodland, for example, isn’t the same as a patch of rough grass—and the metric recognises that.
If your land is being developed—or if you’re creating a biodiversity gain site to sell units—you’ll need a qualified ecologist to do the number crunching.
The ecologist surveys the land, inputs data into the statutory metric spreadsheet, and calculates the biodiversity units gained or lost. Local planning authorities will then review the submitted figures as part of the planning process.
For small developments (like self-builds), there’s a simplified version called the Small Sites Metric (SSM), which is easier and quicker to use—but still needs a competent person to complete.
Since February 2024, all planning applications subject to BNG must use the official statutory version of the biodiversity metric. This replaced older versions like Metric 3.1 or 4.0, which were used voluntarily before BNG became law.
So, if you're still working off an old spreadsheet from a previous woodland plan—time for an upgrade. The statutory version is the only one that planning authorities will now accept.
If you're considering selling biodiversity units or restoring habitats for conservation or income, the metric helps you understand what your land is worth in biodiversity terms.
It can also show you how different land-use choices affect that value. For example:
This helps landowners like Thomas make smart, financially sound decisions before investing time, money, or grant funding.
Not really. The rules are strict, and local planning authorities are trained to spot poor-quality submissions. Biodiversity units must be backed by evidence, verified by ecologists, and managed long-term—often under legally binding agreements.
That’s good news. It keeps the system credible and protects landowners who are doing things properly from being undercut by quick-fix schemes.
The biodiversity metric is what makes BNG work. It takes something as complex as “nature” and gives us a clear, consistent way to measure it—whether you’re a developer applying for planning permission, or a landowner looking to create wildlife-rich habitats with long-term value.
Want to understand how many biodiversity units your land could offer? Start with a conversation—and the right metric tool. At AskGrant, we’re here to help you make sense of the numbers, explore your land’s potential, and connect you with trusted experts who know the system inside out.
Whether you're just curious or ready to take the next step, we’re always happy to chat.
