The short answer
A garage conversion typically costs £6,000–£20,000 in 2026, with most complete single-garage conversions landing around £10,000–£20,000 once insulation, damp-proofing, the door infill and a finished room are included. A simple conversion into a basic room sits toward the lower end; a kitchen, bathroom or fully fitted en-suite bedroom sits at the top. The garage type, its condition, the room you want and the level of finish all move the price. These are typical illustrations, not quotes — see the cost per square metre guide for a closer breakdown.
Converting a garage is one of the more cost-effective ways to add living space to a UK home, because the structure, roof and foundations are already in place. The range of figures quoted — from a few thousand pounds for a basic room to twenty thousand or more for a kitchen or en-suite — can make it hard to know what is reasonable. This guide sets out realistic 2026 ranges, explains what drives the differences, and flags the scenarios that push costs up so there are no surprises in a quote. All figures are typical illustrations rather than quotes, and the work should be carried out by a garage conversion specialist who handles building control.
Garage conversion costs at a glance
- Basic single-garage conversion (simple room) £6,000–£10,000
- Full single-garage conversion (finished room) £10,000–£20,000
- Conversion into a bedroom with en-suite £15,000–£25,000+
- Conversion into a kitchen or utility £12,000–£25,000+
- Double-garage conversion £15,000–£30,000+
- Usable space from a single garage ~13–18m²
What a typical single-garage conversion costs
For most UK homeowners, converting an integral or attached single garage into a habitable room is the starting point. A basic conversion into a simple, plastered and decorated room generally costs £6,000–£10,000, while a fully finished room with good insulation, flooring, electrics and the structural infill of the door opening usually lands at £10,000–£20,000. Location matters: London and the South-East are typically 10–20% higher than the national average. Because the shell already exists, the cost is mostly in upgrading the floor, walls and roof to habitable standard, infilling the door, and fitting out the room. See our cost per square metre guide for figures by finish level.
| Conversion type | Typical cost (2026) | Usual scope |
|---|---|---|
| Basic single garage | £6,000–£10,000 | Simple plastered, decorated room |
| Full single garage | £10,000–£20,000 | Insulated, finished, door infilled |
| Bedroom with en-suite | £15,000–£25,000+ | Plumbing, drainage, fitted bathroom |
| Kitchen or utility | £12,000–£25,000+ | Plumbing, drainage, units, appliances |
| Double garage | £15,000–£30,000+ | Larger floor area and finishes |
What the money is spent on
The bulk of a garage conversion budget goes on bringing the space up to habitable standard rather than on cosmetics. The main items are: damp-proofing and insulating the floor, walls and roof to meet building regulations; infilling the garage door opening with a wall, window or door; upgrading or adding electrics, heating and ventilation; and plastering, flooring and decorating. Rooms that need water — a kitchen, utility or bathroom — cost more because of the plumbing and drainage involved. For the full breakdown of the work, see what is involved in a garage conversion and damp-proofing and insulating a garage conversion.
What pushes costs up
Several factors can push a garage conversion above the typical ranges:
- Wet rooms — a kitchen, utility or en-suite needs plumbing and drainage, often the single biggest cost driver. See converting a garage into a kitchen or utility.
- Detached or poorly built garages — a detached garage, or one with thin single-skin walls or a low floor, may need more structural and damp work.
- Raising or lowering floor levels — garage floors are often lower than the house; bringing them level adds cost.
- Underpinning or foundation work — some older garages have shallow foundations that need strengthening.
- Higher specification finishes — better flooring, joinery, glazing and heating all add to the figure.
Planning, building regulations and value
Most garage conversions do not need planning permission because converting within the existing footprint usually falls under permitted development — though this does not apply to flats, listed buildings or homes in conservation areas. Building regulations always apply, however, and the work must be signed off by building control. Factor this into the budget. A well-executed conversion adds usable living space and can support a home’s value, though it is rarely a direct pound-for-pound return. See planning permission, building regulations and does a garage conversion add value. This is general information; costs vary with your specific garage and the quotes you receive, and the work should be carried out by a garage conversion specialist who handles building control.
Compare garage conversion quotes
Prices vary significantly between builders for the same conversion and scope. Use our service to compare quotes from FMB-registered or building-control-approved specialists in your area.
Frequently asked questions
How much does it cost to convert a single garage?
A full single-garage conversion into a finished, insulated room typically costs £10,000–£20,000 in 2026, while a basic plastered-and-decorated room can start nearer £6,000. A kitchen, utility or en-suite costs more because of plumbing and drainage. These are typical illustrations, not quotes — get at least three itemised estimates for your property.
Is a garage conversion cheaper than an extension?
Usually, yes — because the structure, roof and foundations already exist, a garage conversion is generally cheaper per square metre than building a new extension. The trade-off is the lost garage space and that you are limited to the existing footprint. See garage conversion vs extension.
Do I need planning permission for a garage conversion?
Usually not — converting a garage within its existing footprint normally falls under permitted development. This does not apply to flats, listed buildings, homes in conservation areas, or where permitted development rights have been removed. Building regulations always apply regardless. See planning permission for a garage conversion.
Does a garage conversion add value to a house?
A well-finished garage conversion that adds a usable room can support a home’s value, particularly where the extra bedroom or reception space is in demand. The exact effect varies by property and area, and losing off-street parking can offset the gain in some locations. See does a garage conversion add value.
Sources & further reading
- Federation of Master Builders (FMB) — guidance on garage conversions, costs and finding registered builders
- Planning Portal — permitted development and planning permission for garage conversions
- GOV.UK / Building Regulations Approved Documents L, B and C — insulation, fire safety and damp standards
- RICS — guidance on home improvements and their effect on value
This is general information, not advice for your specific property or conversion. Costs, timescales and outcomes vary with your garage, the room you choose and your chosen builder. The work should be carried out by an FMB-registered or building-control-approved garage conversion specialist. We are an independent information and introduction service, not a builder.