Page Building Consultants
Extension cost calculator
Free Tool

Extension Cost Calculator

Get an instant ballpark estimate for your home extension or loft conversion. Answer 4 quick questions and we'll calculate a realistic cost range based on live UK market rates.

Takes 60 seconds
Based on real UK pricing
No sign-up required

Your Project Details

1

What type of project?

2

Approximate floor area (m²)

5 m² (small)50 m² (typical)100 m² (large)
3

Specification level

4

Project location

5

Optional extras

Select any features you plan to include

Your estimate will appear here

Complete steps 1–4 on the left to generate your instant ballpark estimate.

Project type
Floor area
Spec level
Location

How accurate is this?

This calculator uses our live pricing database and regional cost factors to produce a realistic ballpark range. Actual costs depend on site conditions, contractor availability, and your final specification. We recommend using this as a starting point, then getting a formal estimate.

Why does location matter?

Labour and material costs vary significantly across the UK. London and the South East typically cost 15–25% more than the Midlands baseline. The North of England and Scotland/Wales are generally 8–10% lower. Our calculator applies these regional factors automatically.

What's next?

Once you have a ballpark figure, the next step is a formal estimate based on your actual drawings and specification. We turn these around within 24 hours, with a 2–3% margin of error. Fees start from £200 + VAT.

Ready for a precise, project-specific estimate?

Send us your drawings and we'll produce a detailed cost plan within 24 hours. No obligation, fees from £200 + VAT.

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Page Building Consultants Ltd • Kemp House, 120 City Road, London EC1V 2NX • Compliant with UK GDPR & PECR • Consent valid for 12 months