Loft Conversion Cost Calculator UK
Get a 2026 UK loft conversion cost estimate in 30 seconds. Enter loft type, size, finish level and region — we'll show realistic low-mid-high figures based on pricing data from 519 UK towns and RICS-indexed 2026 labour rates. No email required.
How This Calculator Works
Our loft conversion calculator combines five inputs (type, size, finish, extras, region) with real 2026 UK pricing data from our 519-town database plus RICS labour indices.
Base Shell Rates (per m²)
- Velux only — £1,200/m²
- Dormer — £1,800/m² (UK's most popular)
- L-shaped dormer — £2,300/m²
- Hip-to-gable — £2,100/m²
- Mansard — £2,500/m² (max space)
Includes: structural steelwork, floor joists, roof modifications, insulation (Part L 2022), one staircase, plastering, standard finishes, electrics (Part P certified), heating extension.
Finish & Regional Multipliers
- Basic 0.85× · Standard 1.00× · Premium 1.35× · Luxury 1.70×
- London 1.35× · South East 1.18× · South West 1.08×
- East of England 1.12× · Midlands 1.00× (baseline)
- North West 0.93× · North East 0.88×
- Scotland 0.95× · Wales 0.93× · NI 0.82×
All estimates add 10% professional fees (architect, structural, Building Regs) and 15% contingency. Shown as low-high band (±15%/+20%) to reflect market variance.
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