Land by postcode · AL area · Welwyn
Welwyn covers the AL6 postcode district, in Hertfordshire. Planning applications here are decided mostly by the Welwyn Hatfield planning authority, with East Hertfordshire covering the rest. Below: what homes sold for, which planning controls apply, and what that means before you sell or develop a plot in Welwyn.
Residential sales recorded by HM Land Registry between 2024-08 and 2026-07 across the AL6 district. This is market context for the town, not a land valuation: what a plot is worth depends on what can be built on it, which these figures do not show.
Sales in 24 months
276
Median sale price
£720,000
Median £ per m² of floor area
£6,533
Median, last 12m vs prior 12m
-3.4%
£725,000 → £700,000
Mix of sales: 49% detached, 25% semi-detached, 17% terraced, 9% flats.
New-build sales 2023–2024: 21 of 297 (7%). A rough proxy for recent building activity: these are homes sold by builders, not development sites.
For each designation on the planning.data.gov.uk register, the share of the 506 live postcodes in AL6 whose centroid falls inside it. This measures postcodes, not land area, and says nothing about any individual plot.
182 of 506 postcodes
50 of 506 postcodes
Welwyn · Ayot St Lawrence · Tewin · Ayot Green
No postcodes in AL6 fall inside: National Landscape (AONB), National Park, Article 4 Direction area.
Flood zones, tree preservation orders, local plan allocations, settlement boundaries and non-designated heritage are not included here and are checked in a full assessment.
36% of postcodes in Welwyn are inside the Green Belt, so Welwyn has land both inside and outside it. Which side of the boundary a plot sits on determines whether the Green Belt tests apply to it at all.
These are town-level facts. The free assessment checks your actual boundary against the same registers and the local plan and tells you plainly what they mean for your plot.
Welwyn is split between planning authorities: Welwyn Hatfield (77% of sampled postcodes), East Hertfordshire (15%). The remaining 8% of postcodes fall under authorities not resolved for this page.
Draw your boundary, tell us what you own, and an architect checks it against these registers and the local plan. Free, no obligation, and you get a straight written answer.
It depends on where the plot sits, not on the town average. Across Welwyn, 36% of postcodes are in the Green Belt and 10% in a conservation area. on Green Belt or National Landscape plots a new home is the exception and needs a specific case, and a replacement dwelling, a conversion or a modest extension is usually the realistic route. Outside those designations the questions that decide it are whether the plot is inside or adjoining the settlement boundary in the local plan, whether it has its own road access, and what is next to it.
No Article 4 direction is recorded for Welwyn, so houses keep their normal permitted development rights for outbuildings and extensions within the size limits. Those rights do not extend to agricultural land, paddocks or a change of use to residential, which normally need permission or prior approval.
Developers look at three things before they talk about price: whether the plot is outside the Green Belt and any National Landscape, whether it sits inside or beside the settlement boundary, and what finished homes sell for. In Welwyn the median sale is £720,000, and only 7% of 2023–2024 sales were new-build homes, so builders have been quiet here. A single plot usually goes to a local builder or a self-builder; a site for five or more homes attracts regional housebuilders, normally through an option or a conditional contract rather than an outright purchase, so the price you see quoted is not the price you receive.
There is no town figure for land, because a plot's value comes from what can be built on it, not from where it is. As a guide, a serviced plot with consent for one house commonly sells for around a third of the finished house value, which in Welwyn would be measured against a £720,000 median sale. The same plot without consent, or inside the Green Belt, is worth a small fraction of that, and a paddock with no realistic route to consent is worth agricultural or amenity value only. The free check tells you which of those your plot is before you talk to anyone about a price.
Computed from open-data records; town-level, not plot-level measurements. Welwyn here means the postcode district whose most common post town is Welwyn. Sales: HM Land Registry Price Paid Data (2024-08-01 to 2026-07-31), © Crown copyright, Open Government Licence. Designations: planning.data.gov.uk (OGL); conservation areas and Article 4 directions are made locally and published on that national register. Postcode centroids: OS Code-Point Open, contains OS data © Crown copyright and database right 2026. Figures computed 2026-10-19.