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Garage Conversion Cost Calculator
Converting your garage could add £25,000–£45,000 to your property value. Calculate your conversion costs for 2026 UK market rates.
1. Garage Type
2. Intended Use
3. Specification
4. Add-Ons (optional)
5. Location
ESTIMATED COST RANGE
Full conversion inc. insulation, electrics & finishes.
⚠️ Ballpark estimate only. Costs vary by property condition.
Garage Conversion FAQs
Do I need planning permission for a garage conversion?
Most garage conversions fall under Permitted Development Rights — you won't need planning permission unless you're in a Conservation Area, AONB, or your garage fronts a highway. Building Regulations approval is always required.
How much value does a garage conversion add?
A well-executed garage conversion typically adds £25,000–£45,000 in property value in London, and £15,000–£30,000 in the rest of the UK. Converting to a habitable bedroom with en-suite delivers the strongest ROI.
Can I convert a detached garage into an annexe?
Yes — a self-contained annexe can include bedroom, bathroom, kitchen and living area. This may require planning permission depending on your council and whether you intend to let it out separately. Building Regulations compliance is mandatory.
How long does a garage conversion take?
A simple integral garage conversion takes 3–6 weeks. A full self-contained annexe or double garage conversion can take 8–14 weeks, especially if structural or utility work is involved.