In partnership with bark

Loft conversion cost calculator

Get an instant, realistic estimate for your project, built on 2026 market rates for your conversion type, size and region.

  • Instant estimate, no waiting and no email required
  • Tailored to your UK region
  • Then compare quotes from vetted local specialists

Get your instant estimate

Five quick details for an instant 2026 estimate.

30 m²
2 windows / rooflights
Your estimated cost · 2026 Updates live
£45,000 – £57,500
approx £1,725/m² South East Dormer

Includes structural work, staircase, insulation to current regs, plastering, electrics and a basic finish. Excludes professional fees and fittings.

Compare quotes from local specialists

Free & no obligation · Powered by bark

Transparent pricing

What your estimate covers

Included in the estimate

  • Main structural work for your chosen loft type
  • New floor structure and staircase installation
  • Insulation to current building regulations
  • Plastering, electrics and heating connections
  • Rooflights or dormer windows you select

Not included

  • Architect and structural engineer fees
  • Planning application and building control charges
  • Bespoke joinery and high-end fixtures
  • Furniture, flooring and decorating beyond basic finish
How it works

From estimate to the right builder

  1. 01

    Get your estimate

    Five quick details and you will see a realistic 2026 cost range instantly.

  2. 02

    Compare local quotes

    We connect you with vetted specialists working in your area.

  3. 03

    Choose with confidence

    Pick the builder whose price and approach fit your project best.

Good to know

Loft conversion calculator FAQs

How accurate is the cost calculator?

It gives an instant estimate based on 2026 national averages for each loft type, size, property and region. It is a realistic starting point. Your final quote depends on your specific property and chosen finishes.

Does it include all loft types?

Yes. You can estimate costs for Velux, Dormer, Hip to gable, L-shaped and Mansard conversions across all UK regions.

What is the difference between an estimate and a quote?

An estimate is a quick guide to average costs. A quote is tailored to your property after a specialist reviews the details. Use the calculator to budget, then compare quotes for exact pricing.

Is the calculator free to use?

Completely free, with no email required to see your estimate. Comparing quotes from specialists is also free and no obligation.

Get an instant loft conversion price

Compare local specialists and get the best price. Free, no obligation.

Compare quotes now