UK construction cost tool

Commercial Building Cost Estimator

Budget a UK commercial build from floor area, building type and region, with risk, fees and VAT broken out.

2026 £/m² Rates 17 Building Types Free No Sign-Up

Calculator Inputs

Tender price escalation of 2.60% a year, forecast from the 3Q2026 index of 233.

Cost Breakdown

Cost Line Basis Amount
Building works before adjustments——
Building works cost——
Capital cost before VAT——
Total capital budget——

Scenario Analysis

Scenario Total Capital Budget Change
UK average location--
Top of the published cost range--
Construction starts 12 months later--
Full early-advice allowances--

Each scenario changes one input and reruns the whole calculation, so the comparison is always against your current settings.

From Budget To Handover

1

Early cost adviceArea, location and an indicative start date are enough to set a capital budget — this tool's own basis, per the Costmodelling budget example dated 1 July 2026.

2

Design and planning applicationMost planning applications are decided within 8 weeks, and 13 weeks in England for unusually large or complex schemes, per GOV.UK.

3

Tender and contract awardAllow 6 to 12 weeks for a tender round; price the tender against the index for your start date rather than today's rate card.

4

ConstructionCostmodelling's 1 July 2026 worked example builds a 4,000 m² office block over 52 weeks, and site duration scales with area and storey count.

5

Handover and final accountThe risk allowance is where variations land — it is sized at 10%–15% precisely because ground conditions and client changes are rarely known at budget stage.

How A Commercial Build Budget Is Built Up

A £/m² rate is only the middle of the story. The published figure for warehouses and stores is £1,100–£1,220 per m² in Costmodelling's typical construction cost schedule, released 1 July 2026, and that single number already carries substructure, superstructure, finishes, services, preliminaries and the main contractor's overheads and profit at 5.5%. It deliberately excludes three things that arrive later: external works, which Costmodelling advises adding at 10%–20% of the building cost; a risk allowance of 10%–15% at early cost-advice stage; and professional fees of 5%–15%, which fall as project value rises. On a £5,290,794 warehouse those three allowances add £2,071,345 before VAT, which is 39% on top of the raw building figure — the reason a rate card and a budget are different documents.

What The £/m² Figures Include — And What They Leave Out

The rates used here come from a schedule covering every Uniclass building entity, published against a tender price index of 233 and a building works value of about £1,000,000. They cover the building only: no land, no external works, no fees, no VAT, and no fittings the client buys directly. Across the whole schedule the cheapest modelled building is £490 per m² and the most expensive £8,240 per m², with a median of £2,500 per m² and a mean of £2,270 per m² carrying a standard deviation of £900 per m². A distribution centre at £540–£600 per m² and a data centre at £3,400–£3,760 per m² are the same method applied to two very different briefs, so picking the right row matters more than refining the arithmetic.

Why The Same Building Costs Different Amounts In Different Places

Construction price indices are published region by region in Costmodelling's regional schedule: Northern Ireland sits at 85, the North East at 93, the South East at 105, Outer London at 111, Inner London at 115, the Scottish islands at 118 and Shetland at 122 against a UK average of 100. The gap between Northern Ireland and Shetland is 43.5%, so the same building that costs £5,000,000 at the UK average costs £4,250,000 at the Northern Ireland index and £6,100,000 at the Shetland index. Local labour availability, haulage distance and the number of contractors bidding all feed these indices, which is why the tool prints the regional adjustment as its own line instead of burying it inside the rate.

Getting The Timing Right: Tender Price Escalation

The tender price index stood at 233 in the third quarter of 2026, with a forecast rise of 2.60% per annum over the following 12 months, while the building cost index — the contractor's own labour and materials measure — reached 248 with a 2.80% per annum forecast, per Costmodelling's construction indices. Pushing a start date out by 12 months therefore adds 2.6% to the works cost before any specification change, and 24 months adds 5.27% because the escalation compounds. The ONS construction output price indices, published 13 August 2026 covering January 2014 to June 2026, are the independent check on the same movement.

VAT, Reverse Charge And Costs That Never Appear In A Rate Card

New non-residential construction in the UK is standard-rated, so 20% VAT turns a £7,362,139 capital cost into £8,834,567 — £1,472,428 that has to be budgeted even when a developer expects to recover it. GOV.UK notes that construction services are taxed at 20%, 5% or 0% depending on the building, and HMRC's reverse charge manual means that between two construction businesses the supplier does not charge VAT and the customer accounts for it instead, unless the customer is an end user. Land, planning application fees, furniture the client buys and the business rates that start after completion all sit outside this estimate.

Common Mistakes When Pricing A Commercial Build

The first mistake is treating the £/m² table as a quotation: it is a national average at a fixed index date, and Inner London at 115 against Northern Ireland at 85 is a 35.3% spread before the building type is chosen. The second is forgetting the project-size adjustment — a £100,000 job runs at a factor of 1.12 and a £10,000,000 job at 0.89, so the same warehouse rate buys noticeably less floor area on a small site. The third is setting risk at 5% and fees at 5% to make a budget fit: the published early-advice guidance is 10%–15% for risk and 5%–15% for fees, and stripping both to the floor moves a budget from tested to unfunded the first time ground conditions change.

Method And Limits

This is an early cost-advice budget, not a tender or a quotation. It rests on the published £/m² schedule at tender price index 233 (3Q2026), regional indices dated 1 July 2026, a log-linear size factor interpolated from the published £100,000 / £1,000,000 / £10,000,000 anchors, and a 2.60% per annum tender escalation forecast.

  • Assumes a mid-range specification and regular site access — abnormal ground conditions, contaminated land, a constrained city-centre plot or a listed-building setting can move a real project well outside the range, and none of them is modelled here.
  • Assumes the whole area sits in one building at one rate — a mixed-use scheme with retail at street level and offices above needs each element priced separately and added together.
  • Assumes the size factor is capped at 1.15 and 0.85 — the published anchors only cover £100,000 to £10,000,000 of building works, so jobs outside that band are held at the cap rather than extrapolated.
  • Does not model land, Stamp Duty Land Tax, business rates, client-supplied furniture, IT and equipment, or planning application fees — budget those separately; the planning application fee itself is set by the Planning Portal fee calculator.
  • Does not model VAT recovery — the 20% shown is a cash cost, and whether you recover it is an accountant's question rather than a calculator's.
  • Does not model contract inflation beyond the 12-month tender forecast — a build running past 2027 needs a fresh index from ONS or BCIS.

Figures checked .

Frequently Asked Questions

What does the £/m² rate include?

Substructure, superstructure, finishes, services, contractor-supplied fittings, preliminaries and the main contractor's overheads and profit at 5.5%. It excludes external works, land, professional fees, VAT and anything the client buys directly.

Does this estimate include VAT?

Yes when the VAT box is set to include it — new non-residential construction is standard-rated at 20%, so a £7,362,139 capital cost becomes £8,834,567. Choose the ex-VAT option if you are a VAT-registered developer budgeting for recovery.

How much contingency should a commercial build carry?

The early cost advice published with the rate schedule is 10%–15% of works cost for risk. A 5% allowance is only defensible once the design is frozen and the ground has been investigated.

Why is my figure different from a quote I was given?

Three usual causes: the regional index (85 in Northern Ireland to 122 in Shetland), the project-size factor (1.12 on a £100,000 job, 0.89 on a £10,000,000 one), and the specification position chosen inside the published range.

Are professional fees really 5%–15%?

Yes — the published guidance is 5%–15% depending on project size, with larger projects generally paying a smaller percentage. Fees cover architects, structural and services engineers, quantity surveyors and the CDM duties.

Does the estimate include land?

No. Land purchase, planning fees, furniture, IT equipment and post-completion business rates are all outside the rate table and outside this calculation.

Sources

Last updated: 2026-10-09. This page gives an early cost-advice estimate only, using published UK national averages. It is not legal, tax, planning or financial advice, and it is not a tender or quotation.

About this tool

Created and maintained by CoryVu. Read how we check our tools and consult the sources and assumptions on this page.

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