Garage Conversion Cost Calculator
Estimate the cost of converting your garage into a living room, office or gym — by garage type, floor area and finish quality, with a full cost breakdown and typical price range.
Estimate only. These are indicative 2026 UK estimates based on typical build rates — this is not a quote. Actual costs vary by region, the existing garage's condition, and planning or building control requirements. Always get itemised quotes from local builders before committing to a project.
Typical range: £16,490 – £22,310
- Build cost
- £15,750
- Insulation and damp-proofing
- £2,250
- Flooring
- £900
- Building control
- £500
- Estimated total cost
- £19,400
How garage conversion costs are calculated
Garage conversion cost mainly depends on the type of garage: an integral garage (built into the house) is cheapest to convert because the walls, floor and roof are already there; an attached garage needs a bit more work; a detached garage needs new services run to it and costs the most. We multiply an indicative build rate per square metre by your floor area and finish quality, add insulation and damp-proofing plus flooring (both priced per square metre), building control fees, and optional add-ons for extending the heating and adding a plumbed ensuite or kitchenette. Treat the result as a starting point for budgeting — always get itemised quotes from local builders, as the existing garage's condition, floor level and access all change the price.