Construction Cost Calculators
Get an instant ballpark figure for your project. Four free calculators built on current UK construction rates — no sign-up required.
House Extension Cost Calculator
Single storey, double storey, side return and wrap-around extensions
Estimated construction cost (excl. VAT)
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Excludes VAT (20%), architect fees, planning application, building control, party wall agreements, structural engineer, and any groundworks surprises. Add 10% contingency for unforeseen costs.
Get a proper estimate from your drawings →Loft Conversion Cost Calculator
Velux, dormer, hip-to-gable and mansard conversions
Estimated construction cost (excl. VAT)
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Excludes VAT (20%), architect or designer fees, structural engineer, building control, party wall agreements and any staircase alterations to lower floors. Add 10% contingency for the unexpected.
Get a proper estimate from your drawings →New Build Cost Calculator
Detached, semi-detached, terraced houses and apartments
Estimated construction cost (excl. VAT & land)
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Excludes land purchase, VAT (typically zero-rated for new builds), architect fees, structural engineer, planning application, building control, utility connections, landscaping and external works. Add 5–8% contingency for a new build on a surveyed site.
Get a proper estimate from your drawings →Basement Cost Calculator
New excavated basements and existing cellar conversions
Estimated construction cost (excl. VAT)
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Basement costs vary significantly depending on ground conditions, proximity to neighbouring foundations, water table depth, party wall obligations and access for excavation. These figures include excavation, waterproofing, structure and basic fit-out only. Add 15–20% contingency — basement projects regularly encounter unforeseen ground issues.
Get a proper estimate from your drawings →