Checking a submitted BNG metric: a free first read for planning authority ecologists

Every statutory biodiversity metric reaches a local planning authority as an Excel workbook of forty-odd tabs, with the tool's own ▲ and ⚠ flags scattered across them, many in columns off the right edge of the screen. GOV.UK's guidance for authorities says LPAs are responsible for reviewing and checking the metric calculations submitted with an application. Quadrat is a free check that reads a submitted metric in your browser and gives you one page back before you open the first tab: what the tool itself has flagged, what would have the file bounced as invalid, and the questions the metric never asks but a reviewer does.

It is made for the consultant ecologists who fill the metric in, so that files arrive clean. The same check reads a submitted file exactly as it reads the consultant's: drop the workbook on the check page, nothing to install, nothing to sign up for.

What it finds in a submitted file

• Whether the file can be accepted at all. The metric version, read from the workbook's own Version History sheet: Metric 4.0 or earlier is refused outright (GOV.UK: LPAs should not accept calculations made with previous versions of the tool), and a statutory metric that is not the current 1.0.4 or small sites metric 1.2.3 is noted. A macro-enabled .xlsm, hidden sheets, a file over the Planning Portal's size limit, and a workbook saved in manual-calculation mode (its flags may be stale) are each named.
• The Start page. Planning authority, project, applicant, application type, reference, who completed the metric and when, the calculation iteration and the target percentage: each blank is listed. The Reviewer cells, which are for the authority, are reported if the applicant has filled them.
• Every flag the tool raised, on one page. Each ▲ (the tool's input error or rule break) and ⚠ (attention required) from the data-entry sheets, the Start page, the headline results, the trading summaries, the credits summary, the off-site summary and the irreplaceable habitats sheet, grouped by sheet and parcel, with the parcel's reference, habitat and User comments cell beside it. Lookup sheets are ignored; they hold reference text, not flags. A Trading rules not satisfied or BNG targets not met buried in a trading summary is counted on the verdict line at the top of the page, not found on the fortieth tab.
• The numbers, copied from the Headline Results sheet. Baseline and post-development units, net change, the percentage against the target, the trading-rule results, whether off-site units are present, and the spatial risk deductions, transcribed so they can be read against the report and the gain plan. Quadrat never calculates a unit; it copies the tool's own.
• What a reviewer asks that the metric never flags. A condition score with an empty User comments cell, worst when the score is Good or a Fairly grade; strategic significance of High or Medium with no comment naming the strategy document; a habitat marked Condition Assessment N/A that the workbook's own lookup says is assessable; a created or enhanced habitat whose time to target condition is over thirty years; a parcel row with a habitat but no area, or an area but no habitat; a blank calculation iteration.
• With the condition assessment workbook beside it, each baseline parcel in the metric is matched to its sheet in the GOV.UK condition workbook by reference, and the page says where the two files the authority received disagree: a parcel in one file and not the other, a condition on the sheet that is not the condition in the metric, a sheet with no result marked, a Good with no justification written on the sheet, a sheet from the wrong habitat group. It reads the result as the surveyor marked it and never re-scores a criterion; where the files disagree it picks neither.

What it cannot tell you

Whether the habitats were identified correctly, whether a condition score is right, whether the baseline date is valid, whether the mitigation hierarchy was followed, or whether the plans match the parcels. Those are the competent person's judgement and the authority's, and Quadrat does not pretend to them. Nor does it apply a local requirement: it reads what the workbook says about itself. GOV.UK asks authorities to check that the pre-development, post-development and net change calculations match, that the trading rules are met, and that the habitat valuations are accurate; Quadrat helps with the first two by putting the tool's own figures and flags on one page, and cannot help with the third.

Nothing leaves the browser

The workbook is read by JavaScript on your own computer. There is no upload, no account, no server that sees the file and nothing recorded about it; the check works with the network disconnected. An applicant's file stays where the authority's own policy keeps it.

One line for a validation checklist

If your authority publishes a local validation list or a BNG submission checklist, this sentence is written to be carried in it as it stands:

Before submitting, run the statutory biodiversity metric workbook through the free check at quadrat.uk, clear every ▲ it reports, and make sure every ⚠ has its evidence in the User comments column.

That asks nothing of the applicant but a clean file, and it costs the authority nothing. Every flag string the metric can raise is explained, one page each, in the glossary, which an applicant's response can be pointed at by name.

Sources

GOV.UK, Biodiversity net gain: what local planning authorities should do (updated 14 July 2026); the statutory biodiversity metric 1.0.4 and small sites metric 1.2.3 workbooks, whose formulas the flag vocabulary is harvested from; the statutory biodiversity metric user guide; the Planning Portal's file rules. Quadrat is not affiliated with Defra, Natural England, the Planning Portal or any planning authority. If you review metrics for an authority and the check misses something a reviewer would ask, write to hello@quadrat.uk; replies are signed as Quadrat.