Barn conversion Cost Calculator
A UK barn conversion costs £1,500–£3,000 per m² in 2026 for the conversion works, rising to £2,200–£4,000/m² for a high-specification, glass-heavy finish. In whole-project terms that's roughly £150,000–£300,000 for a small 100m² barn, £300,000–£600,000 for a typical 200m² barn, and…
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2 steps, using the figures from our cost guide.
How this calculator works
Every figure in this calculator is the one published in the cost table on our barn conversion guide. Pick the option that matches your job and the calculator returns that published range, adjusted for your region - it does not model anything the guide does not already say.
That is deliberate. A calculator whose rates drift from the page it sits under is worse than no calculator, because two numbers on the same site disagree.
What it cannot know: access, the condition of what is already there, and anything structural. Those are what separate three real quotes from each other.
Published barn conversion costs (2026)
| Option | Typical 2026 cost | Notes |
|---|---|---|
| Small (100m²), standard finish | £150,000–£200,000 | |
| Medium (200m²), standard finish | £300,000–£400,000 | |
| Large (300m²), standard finish | £450,000–£600,000 | |
| Small (100m²), mid-range finish | £200,000–£280,000 | |
| Medium (200m²), mid-range finish | £400,000–£560,000 | |
| Large (300m²), mid-range finish | £600,000–£840,000 | |
| Small (100m²), high-end finish | £280,000–£400,000 | |
| Medium (200m²), high-end finish | £560,000–£800,000 |
These are the figures from our barn conversion cost guide.
What drives a barn conversion’s cost
The calculator gives you a starting band, but two barns of the same floor area can be tens of thousands of pounds apart. The biggest variable is the structure you start with. A sound, watertight frame that only needs insulating, glazing and fitting out sits near the bottom of the range; a leaning stone barn that needs underpinning, a new roof and a steel frame to hold it up can double the figure before you have chosen a kitchen. That is why the guide quotes a per-square-metre band of roughly £1,500–£3,000 rather than a single rate — see the full barn conversion cost per m² breakdown for where a job lands within it.
Getting services to a rural site is the cost most people forget. Bringing mains electricity, water and drainage across a field, or installing a septic tank and a heat pump where there is no gas main, can add a five-figure sum that has nothing to do with the walls. Planning conditions do the same: a conversion under permitted development (Class Q) comes with limits on how much you can rebuild, while a full application in open countryside often carries conditions on materials, window openings and landscaping that push up the spec. Access for lorries and a crane, a party wall agreement with a neighbour, and whether the barn is listed all move the number too.
One thing can move in your favour. Converting a building that has not been lived in into a home can qualify for a reduced 5% rate of VAT on most of the construction work under HMRC’s rules for conversions (VAT Notice 708) rather than the standard 20% — a real saving worth confirming with a VAT-registered builder before work starts. We cover it in is a barn conversion VAT-free?, and whether the whole project stacks up in is a barn conversion worth it?
Barn conversion calculator — FAQs
It uses the same published figures as the cost guide it sits under, adjusted for your region. It is a budgeting estimate, not a quote - only a site visit produces one of those.
Mostly the structure you inherit and the site. A sound frame that just needs insulating, glazing and fitting out sits at the bottom of the range; a barn that needs underpinning, a new roof or a steel frame to stay standing costs far more. Getting mains services or drainage to a rural plot, planning conditions on materials and window openings, and difficult access for machinery all add up before any of it shows in the finished rooms.
Often, yes. Converting a building that has not been used as a dwelling into a home can qualify for a reduced 5% rate of VAT on most of the construction work under HMRC’s rules for conversions (VAT Notice 708), instead of the standard 20%. A VAT-registered builder applies the reduced rate on your invoices, so confirm it before the job starts — on a six-figure project the difference is substantial.
Related cost guides
- Barn conversion cost guide — The full price guide
- All builders services — Browse the hub
- All BestBuilders services — Every trade we cover
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