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New build calculator

What building it from nothing costs, from the ground to the handover

A new dwelling is the one job where the tax works in your favour: the construction is zero rated for VAT, which is worth a fifth of the bill against any refurbishment of the same size. Against that, the site costs that do not exist on an existing building are real money: the services, the drainage, the roads, the warranty and the planning obligations. This prices all of it.

For: A new build from scratch, or a demolish and rebuild

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What you are building
m²
Gross internal area, which is what a builder prices. A three bedroom house is about 110 square metres and a generous four bedroom one about 180.
More than one and the site costs spread, the trades get more efficient and the per-unit price falls.
The cheapest shape to build, and the baseline these rates are quoted at.
Level of specification
What most one-off houses actually get built to. Better glazing, a proper heating design, and some detail worth looking at.
How it gets built
One contract, one programme and one number. The most expensive and the least of your time.
Region
Site costs
These do not exist on a refurbishment, and on a first new build they are the whole overspend. Nobody knows what the ground is like until somebody digs a hole in it.
£
Taking an existing building down to slab level is also what zero rates the VAT on what replaces it, so it can pay for a good part of itself.
£
Piling, deep foundations, contamination, a high water table, a diverted sewer, a retaining wall or rock. A ground investigation costs £2,000 to £5,000 and is the best money you will spend on the whole project.
£
Electricity, water, gas and telecoms brought to the boundary and connected. Quoted by the network operators, not by your builder, and the lead times run to months. Budget £10,000 to £20,000 on a serviced plot and far more where the mains is a field away.
£
A mains connection is the cheap answer. A soakaway, an attenuation tank or a treatment plant where there is no mains drainage is several times that, and it is usually a planning condition rather than a choice.
£
Including a dropped kerb and any road opening the council requires, which they do and charge for.
£
Usually a planning condition, so it is not optional, and it is the line that gets cut when the money runs out in month fourteen.
£
Fees, consents and the warranty
%
Architect, structural engineer, SAP calculations, a quantity surveyor and site inspections. Eight to twelve per cent on a one-off house, and the drawings for a new dwelling are a great deal more work than for an extension.
£
£610 per dwelling for fewer than ten from 1 April 2026, and £659 each between ten and fifty. Plus the Planning Portal charge and whatever the supporting reports cost, which is usually the larger number.
£
A full plans application on a new dwelling, with inspections at every stage through to the completion certificate.
£
Ten years. Not legally required and effectively compulsory: no mainstream lender will lend to your buyer without one, and it has to be arranged before work starts rather than afterwards.
£
Set by each charging authority per square metre of new floorspace, and payable on commencement rather than on sale. A genuine self-builder can claim full relief, and the claim has to be made and acknowledged before work starts: miss the paperwork and the whole levy becomes payable.
%
Ten per cent on a straightforward plot with a ground investigation done. Fifteen or more on anything sloping, backland or previously built on.
Are you the self-builder?
A contractor zero rates their labour and materials directly. Anything you buy yourself is charged at 20% and reclaimed afterwards under the DIY Housebuilders Scheme, in one claim, within six months of completion. Budget the cash flow for it: you carry that VAT for the whole build.
A new dwelling, all in£493,293 to £611,373£3,083 to £3,821 a square metre across 160 m², and about 41 weeks on site. The construction is zero rated for VAT, which saves roughly £87,800 against the same job on an existing building. Excludes the land. Published guides put a new build at £1,800 to £3,500 a square metre by specification, and £1,900 in the north to £4,500 for a bespoke architect-designed house in London.
£352,000 to £448,000Construction
£39,000Site and externals
£48,610 to £58,210Fees and warranty
£87,800VAT saved
Construction74%Site and externals7%Fees and warranty10%Contingency9%
Built up
Construction£352,000 to £448,000
160 m² at £2,200 to £2,800 a square metre, multiplied by 1.00 for West Midlands. Substructure to handover, excluding everything outside the walls.
Site and externals£39,000
9% of the construction cost. On a serviced plot this runs 10% to 15%; above 25% the site is doing something expensive and it is worth understanding what before you commit.
Professional fees£48,610 to £58,210
10.0% of the build plus planning, building control and the warranty. Unlike the construction, these are standard rated for VAT, which is why the total below is not entirely VAT free.
Contingency£43,961 to £54,521
10%. On a new build the contingency is mostly for the ground, which is why a ground investigation before you commit is worth several times what it costs.
VAT on the fees£9,722 to £11,642
The construction is zero rated. The professional fees are not, and this is the part that surprises people who were told a new build has no VAT on it.
All in£493,293 to £611,373
Excluding the land, the stamp duty on it, and the finance.
The VAT position
Saved by it being a new dwelling£87,800
Twenty per cent of the construction cost. The same work on an existing house you live in would be standard rated with no relief at any scale, which is the single largest financial difference between building and extending.
VAT you have to fund and reclaim£36,000
Roughly the materials share of the build, if you buy materials yourself rather than through a contractor. Charged at 20% and reclaimed under the DIY Housebuilders Scheme in a single claim within six months of completion, so you carry it for the whole build. Keep every invoice: no invoice, no reclaim.
Programme and cash flow
Weeks on site41 weeks
About £13,472 a week. Services connections and the warranty inspector both have lead times measured in months, so start them before you need them.
Before a spade goes in the ground£30,874
Design, planning, building control, the warranty and a large share of the fees, all payable before there is anything to look at. This is the phase that catches out first-time self-builders.
Per unit£493,293 to £611,373
Where these figures come from

Build rates. UK new build at 2026 prices: budget £1,800 to £2,200 a square metre, mid range £2,200 to £2,800, high end £2,800 to £3,500 and above. An average self build is likely to cost £2,500 to £3,000. Regionally, from about £1,900 a square metre for a standard specification house in the north to £4,500 or more for a bespoke architect-designed house in London. These are core building work and exclude land, professional fees and external works.

Fees. A full planning application for a new dwelling is £610 per dwelling below ten from 1 April 2026, and £659 each for ten to fifty. Structural warranties run ten years and are effectively required by lenders.

VAT. The construction of a new dwelling is zero rated, including on a site cleared to slab level by demolition. Professional fees are standard rated. Self-builders reclaim VAT on materials under the DIY Housebuilders Scheme in a single claim within six months of completion.

CIL is charged per square metre of new floorspace under each charging authority's published schedule and is payable on commencement. Self-build relief is available and must be claimed, and acknowledged, before work starts.

Excludes the land, the stamp duty on it and the finance. Site costs are where new builds overspend, and the only way to know about them before committing is a ground investigation, which costs a few thousand pounds and routinely saves tens of thousands. Services connections are quoted by the network operators rather than by your builder and the lead times run to months, so they belong on the programme from week one. The self build VAT reclaim is a single claim made within six months of completion and it depends entirely on holding the invoices, so keep them from the first delivery. CIL self-build relief has to be claimed and acknowledged before work commences; starting first makes the whole levy payable and there is no discretion in it. An estimate, not a quotation.

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