Development
Step 03 · Build Costs
BCIS benchmarking

AI Build Cost Calculator

Generate BCIS-aligned cost estimates with regional adjustments, contingencies, and professional fees. The AI explains cost drivers and flags potential risks.

AI-Powered
Free to use
1PD
2GDV
3Build
4Finance
Cost breakdown
We itemise major cost categories for transparency.
  • Base construction (shell & core)
  • M&E and internal finishes
  • Professional fees & contingency
Project specification
Define scope to estimate total build cost.
AI RECOMMENDATION
Build Cost Analysis
Ready
Live

Input your gross internal area, build type, and specification level. The AI will reference BCIS data and regional adjustments to produce a detailed cost estimate with contingencies.

TOTAL COST

£2.25m

COST/SQM

£2,741

Confidence91%
Cost breakdown
Major cost categories
Base construction£1,824,500
Contingency (10%)£182,450
Professional fees (12%)£240,834
Total build cost£2,247,784
Loading...
Total cost

£2.25m

All-in budget

Cost per sqm

£2,741

+3.2%

BCIS-aligned

Cost per sqft

£255

For UK/US comparison

Risk buffer

10.0%

Contingency allocated

About the Build Cost Calculator

What it does and how it helps you

The Build Cost Calculator helps UK property developers estimate construction costs using BCIS-aligned benchmarks. Calculate accurate build costs including regional adjustments, contingencies, and professional fees for new builds, conversions, refurbishments, and extensions.

BCIS-aligned construction cost benchmarks for accurate UK estimates
Regional multipliers covering all UK regions from London to Scotland
Multiple build types: new build, conversion, refurbishment, extension
Specification levels from basic social housing to premium high-end

How It Works

Understanding the calculation method

The Build Cost Calculator uses BCIS (Building Cost Information Service) data to estimate construction costs: 1. Base Costs - Select your build type (new build, conversion, refurbishment, or extension) and specification level (basic, standard, or premium) 2. Regional Adjustments - Apply location multipliers based on UK region (London attracts 25% premium, North typically 5% below base) 3. Contingencies - Add contingency percentage (typically 7.5-15%) for unforeseen costs 4. Professional Fees - Include architect, engineer, QS, and project management fees (typically 10-15% of build costs) The calculator provides cost per sqm, cost per sqft, and total project cost with full breakdown of all components.

When to use this calculator

Use this calculator during feasibility stage to estimate total construction costs for development appraisals. Essential for calculating profit on cost, structuring development finance, and determining residual land value. Particularly useful when comparing different build types or specification levels.

Frequently Asked Questions

Common questions about this calculator

BCIS (Building Cost Information Service) is the UK's leading provider of construction cost data. It's produced by RICS and provides industry-standard cost benchmarks. Lenders, quantity surveyors, and professional developers use BCIS data to validate build cost estimates in development appraisals.
Contingency typically ranges from 5% for straightforward new builds to 15% for complex conversions or heritage projects. Standard practice is 7.5-10% for most schemes. Lenders will stress-test your appraisal with higher contingency, so budget conservatively. Remember: unused contingency becomes profit, but insufficient contingency can kill a deal.
Professional fees cover architects (3-5%), structural engineers (1-2%), MEP consultants (1-2%), quantity surveyor (1-2%), project manager (2-3%), planning consultant (0.5-1%), and building control (0.5-1%). Total professional fees typically range from 10-15% of build costs depending on project complexity.
UK construction costs vary significantly by region. London commands 20-30% premium over Midlands baseline. South East adds 10-15%, South West 5-10%, while North and Scotland are typically 5-10% below baseline. This reflects labour costs, material transport, and supply/demand dynamics. Always use regional multipliers in your appraisals.
GIA (Gross Internal Area) includes all internal space including walls and columns. NIA (Net Internal Area) excludes walls, columns, and service areas. Construction costs are always quoted per sqm of GIA as this is what you're building. Sales values use NIA as this is usable space. For residential, GIA is typically 10-15% larger than NIA.

Related Property Terms

BCIS construction costs UKBuild cost calculator per sqmDevelopment appraisal build costsConstruction contingency percentageProfessional fees developmentCost per sqm LondonNew build costs calculatorConversion build costs UKQS build cost estimateRegional construction costs UK