"Is my land in the green belt?" decides more purchase and design decisions than almost any other planning question — and the answer is a boundary line, not a guess. This checker tests your postcode against the national green belt dataset and, just as importantly, explains what a yes actually means for what you want to build.
Check your postcode
The checker needs JavaScript. The dataset is on planning.data.gov.uk.
What green belt status really means
Green belt is a policy line, not a beauty contest — its purpose is to stop towns merging and to keep land permanently open. Inside it, national policy treats most new building as inappropriate development, approvable only in "very special circumstances". But the exceptions are where real projects live:
- Extending an existing house — allowed if not disproportionate to the original building. Councils often express this as a percentage uplift; check your local plan. Permitted development also still applies in the green belt (test yours with the extension PD checker).
- Replacement dwellings — acceptable where not materially larger than what they replace.
- Limited infilling in villages, and redevelopment of previously developed land that does not harm openness.
- Agriculture, forestry and outdoor sport buildings and uses appropriate to the countryside.
- New open-market housing beyond those exceptions — the hardest case in English planning, requiring very special circumstances or a plan-led release of land.
Reading a "yes" like a professional
Being in the green belt does not end a project — it reframes it. The proportionality of an extension, the openness impact of an outbuilding, and the fallback position under permitted development all become the currency of the argument. What kills green belt applications is ignoring the designation; what wins them is designing to its tests from day one, with the technical evidence — flood, daylight, landscape and biodiversity — done properly.
Honest limits
This is a point check at the postcode's coordinates against the national dataset: plot boundaries near a green belt edge deserve a look at the council's own policies map, and Wales and Scotland designate green belts separately from this England dataset. For every other designation at the same time, run the full site constraints appraisal.
How Fortress Associates can help
Green belt schemes live or die on evidence quality. Our free automated reports — FRA, AQA, energy, sustainability — plus professional daylight assessments give a green belt application the technical backbone officers expect. Start with the document checklist or talk to us.
Sources & further reading
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