A garage conversion in the UK typically costs £10,000 to £20,000 in 2026, with an average of around £15,000 for a standard single garage of about 16m². That works out at roughly £625–£1,250 per m², which is much cheaper than a typical extension at £1,800–£3,000 per m². Detached garages cost more, around £15,000–£25,000, and a double garage conversion can cost £20,500–£45,000.
This guide explains what a garage conversion costs by type and use, what is included, the extra costs to plan for, and how much it costs to build a new garage instead.
Garage Conversion Cost UK 2026: Quick Summary
| Type of garage conversion | Typical cost | Average |
|---|---|---|
| Integral garage | £10,000 – £14,000 | £12,000 |
| Attached garage | £10,000 – £20,000 | £15,000 |
| Detached garage | £15,000 – £25,000 | £20,000 |
| Double garage (around 36m²) | £20,500 – £45,000 | £32,750 |
| Carport to garage | £10,500 – £22,000 | £16,250 |
| Partial conversion | £5,500 – £8,500 | £7,000 |
Figures are based on 2026 UK cost guides from Checkatrade and MyBuilder (sources listed at the end) and include VAT unless stated. Prices vary by location, garage condition, size and specification. Use them as a guide, not a quote.
How Much Does an Integral Garage Conversion Cost?
An integral garage conversion usually costs £10,000 to £14,000, with an average of around £12,000. An integral garage is built inside the main footprint of the house, so it already shares walls, a roof and often services with the home. That makes it the cheapest type to convert, because less work is needed to connect it to the rest of the house.
How Much Does an Attached Garage Conversion Cost?
An attached garage conversion typically costs £10,000 to £20,000, with an average of around £15,000. An attached garage shares one wall with the house. The cost depends on the condition of the walls and roof, how much insulation is needed, and whether you knock through to the house.
How Much Does a Detached Garage Conversion Cost?
A detached garage conversion usually costs £15,000 to £25,000, with an average of around £20,000. Because the garage stands apart from the house, new connections for electricity, water and drainage are usually needed. Detached garages are often used as home offices, gyms, studios or annexes.
How Much Does a Double Garage Conversion Cost?
A double garage conversion typically costs £20,500 to £45,000, with an average of around £32,750 for around 36m². An integral double garage is at the lower end, while a detached double garage, or one with a bathroom or kitchen, is at the higher end.
Garage Conversion Cost per m²
As a guide, a garage conversion costs around £625–£1,250 per m². That is much less than a new extension, which typically costs £1,800–£3,000 per m², because the walls, roof and foundations are already in place.
Garage Conversion Cost by Room
| What you convert the garage into | Typical cost |
|---|---|
| Bedroom or home office | £10,000 – £20,000 |
| Bedroom with en-suite or bathroom | add £5,500 – £9,000 |
| Kitchen or utility room | add £15,000 – £35,000 |
Rooms with water, such as kitchens, bathrooms and utility rooms, cost more because of new plumbing, drainage and extraction.
Garage Conversion Cost Breakdown
A standard garage conversion is usually made up of these main items:
| Item | Typical cost |
|---|---|
| Remove the garage door and build a new wall | £1,300 – £1,500 |
| New window and door | £1,200 – £1,500 |
| Raise and insulate the floor | £1,000 – £1,250 |
| Stud wall | £750 – £950 |
| Plumbing and pipework | £1,000 – £3,000 |
| Electric sockets | £90 – £100 each |
| Architect drawings | around £2,000 |
| Structural engineer | £500 – £1,000 |
Other costs include insulation to the walls and roof, plastering, heating, lighting, flooring and decoration. A line-by-line estimate shows each item separately, so you can compare builders' quotes fairly.
What Affects the Cost of a Garage Conversion?
- Type of garage: integral is cheapest, detached and double garages cost more.
- Condition: a single-skin wall, damp, or a poor roof adds work.
- Floor level: garage floors are usually lower than the house and need raising and insulating.
- Use of the room: kitchens and bathrooms add plumbing and drainage costs.
- Knocking through: opening up to the house may need a steel beam or lintel.
- Location: London and the South East are usually more expensive.
Do You Need Planning Permission for a Garage Conversion?
Many garage conversions in England do not need planning permission, because the work is mainly internal and falls under permitted development. However, permission may be needed if the outside of the building changes significantly, if the property is listed or in a conservation area, or if permitted development rights have been removed, which is common on newer housing estates. Always check with your local planning authority.
A garage conversion almost always needs Building Regulations approval, because the garage becomes a habitable room. This covers foundations, damp-proofing, insulation, ventilation, fire safety and escape. You will need building regulations drawings for your application.
How Long Does a Garage Conversion Take?
Most garage conversions take around 2 to 4 weeks on site. Larger or detached conversions, and those with kitchens or bathrooms, take longer. Allow extra time before work starts for drawings and approvals.
How Much Does It Cost to Build a Garage in the UK?
If you do not have a garage, or want a new one, building a garage is a separate project. As a guide:
| Type of new garage | Typical cost |
|---|---|
| Single brick garage, flat roof | £18,000 – £26,000 |
| Single brick garage, pitched tiled roof | £22,000 – £36,000 |
| Double brick garage, flat roof | £28,000 – £44,000 |
| Double brick garage, pitched tiled roof | £38,000 – £50,000 |
| Prefabricated garage | £1,000 – £8,000 |
Garage build costs come from guides published between 2023 and 2026, so current prices may be higher. A new garage needs foundations, a slab, walls, a roof and a door, and may need planning permission depending on its size and position.
Garage Conversion vs Extension
A garage conversion is usually much cheaper and quicker than an extension, because the structure already exists. However, you lose parking and storage space. If you need more room than the garage can give, compare our house extension cost guide and loft conversion cost guide.
How to Get an Accurate Garage Conversion Price
Average prices are a useful starting point, but the only way to know what your conversion will cost is to price it from drawings. At Nextron Estimating, we prepare detailed estimates and drawings for UK builders and contractors.
- House extension and conversion estimating: an itemised price from your drawings
- Building regulations drawings: for your Building Control application
- Planning drawings: where planning permission is needed
Frequently Asked Questions
How much does a garage conversion cost in the UK?
Most UK garage conversions cost £10,000–£20,000 in 2026, with an average of around £15,000 for a standard single garage.
How much does a double garage conversion cost?
A double garage conversion typically costs £20,500–£45,000, with an average of around £32,750.
How much does a garage conversion cost per m²?
Around £625–£1,250 per m², much less than a typical extension.
How much does it cost to convert a garage into a bedroom?
Usually £10,000–£20,000. Adding an en-suite or bathroom adds around £5,500–£9,000.
How much does it cost to build a garage in the UK?
A single brick garage typically costs £18,000–£36,000 and a double brick garage £28,000–£50,000, depending on the roof type. Prefabricated garages are much cheaper.
Do I need planning permission to convert my garage?
Often not, as many conversions are permitted development. Check whether your permitted development rights have been removed. Building Regulations approval is almost always required.
How long does a garage conversion take?
Usually 2–4 weeks on site, plus time for drawings and approvals.
Sources
- Checkatrade: Garage conversion cost guide
- Checkatrade: Cost to build a garage
- MyBuilder: Garage build costs
Get a Garage Conversion Estimate
Send us your drawings and we will prepare a clear, itemised estimate for your garage conversion. If you want to see our format first, ask for a free sample estimate.
Call us on +44 7576 532125, or email info@nextronestimating.co.uk.
