Garage Conversion Cost UK and Kent, £6,000 to £25,000+

A garage conversion in the UK costs from about £6,000 for a basic single garage to £25,000 or more for a premium or double conversion, according to Less's 2026 cost guide. The national average is about £14,000, and about £15,000 in the South East, which includes Kent. A simple home office or playroom costs less than a bedroom with a bathroom, because plumbing adds £1,500 to £4,000.

From working with clients across Kent, we’ve found that garage conversions are often one of the most cost effective ways to create additional living space. In our experience, a garage conversion works better than a small extension because you are usually working within an existing structure, which reduces both construction time and overall costs.

Homeowners often underestimate the impact a well designed garage conversion can have on how they use their home.

Average garage conversion costs in the UK

The overall garage conversion cost depends on several factors. The cost guide published by Less, last updated in October 2026, gives these typical UK ranges.

• Basic single garage with no plumbing, £6,000 to £15,000
• Integral garage, £8,000 to £18,000
• Single garage with a bathroom, £12,000 to £25,000
• Double garage, £15,000 to £30,000

The same guide puts the average mid range single conversion at £14,000, and at about £15,000 in the South East, which includes Kent.

These figures will vary depending on location, materials, plumbing requirements, and structural alterations.

Single and double garage conversion costs

Less's figures split clearly by the size and type of garage. A basic single garage conversion costs £6,000 to £15,000, about £10,000 on average, and £12,000 to £25,000, about £18,000 on average, once a bathroom goes in. An integral garage, built into the house, averages about £12,000, and a detached garage about £20,000.

A double garage gives you roughly 23 square metres, which is enough for an open plan living space, a kitchen diner or two separate rooms. Less puts converting one at £15,000 to £30,000, about £22,000 on average.

What each part of a garage conversion costs

The same guide breaks a single garage conversion down like this.

Heating is not priced separately in the guide. For each stage of the work, see what is involved in a garage conversion.

What affects garage conversion cost?

Several factors influence the final cost of the project.

Insulation and thermal upgrades

Most garages were not originally built as living spaces, which means insulation is often required for walls, floors, and ceilings.

This is one of the most important investments within the project because it directly affects comfort and energy efficiency.

In practice, what we often see is homeowners focusing on finishes while overlooking insulation. However, the quality of the insulation often determines how comfortable the room feels throughout the year.

Windows and doors

Replacing the garage door with a wall and window is one of the most common elements of a conversion.

The size, style, and specification of the window can significantly affect costs, particularly if energy-efficient glazing is selected.

Plumbing and bathrooms

Adding plumbing increases the overall garage conversion cost. If you want a bathroom, utility room, or kitchenette, additional drainage and water supplies may be required.

From working with clients, we’ve found that adding a bathroom often increases costs substantially but can also improve the flexibility of the new space.

What rooms are most commonly created?

Garage conversions can be used for many purposes, including:

• Home offices
• Additional living rooms
• Playrooms
• Bedrooms
• Utility rooms
• Home gyms

In our experience, a home office works better than a rarely used guest room because it delivers everyday value and reflects how many homeowners now use their properties.

Over the last few years, dedicated workspaces have become one of the most requested garage conversion projects we undertake.

Converting a garage into a bedroom

Less puts a garage turned into an extra bedroom at £10,000 to £18,000, and says adding an en suite pushes the cost towards the upper end. With a bathroom included, its figures for a single garage run from £12,000 to £25,000.

A bedroom also has to meet the fire safety rules for a room people sleep in. On the ground floor, every habitable room other than a kitchen needs either a door straight onto a hall that leads to an exit or an emergency escape window or door, as Approved Document B sets out. A converted garage often opens off a utility room or kitchen rather than the hall, so where the door goes, or whether the new window can double as an escape window, is worth settling at the design stage.

Garage conversions versus extensions

Many homeowners compare a garage conversion with building an extension.

Projects involving extensions and conversions both create additional living space, but the costs can differ significantly.

In our experience, a garage conversion works better than a comparable extension when budget is the primary concern because much of the structure already exists.

Extensions often require:

• New foundations
• External walls
• Roofing work
• Larger structural alterations

A garage conversion can avoid many of these costs while still creating a highly functional room.

Garage conversion cost per square metre

Less puts a garage conversion at £700 to £1,700 per square metre, against £1,500 to £2,500 per square metre for a single storey extension. The gap is the structure that already exists. A conversion keeps the garage's foundations, walls and roof, where an extension has to build all three. For what a new extension costs in full, see how much a house extension costs in the UK.

Planning permission and building regulations

Many garage conversions fall under permitted development rights, meaning planning permission may not be required.

However, requirements vary depending on the property and location. Checking through the Planning Portal helps confirm what approvals may be needed.

All garage conversions must comply with Building Regulations. These regulations cover insulation, ventilation, fire safety, structural integrity, and other key areas.

Inspections may be carried out by Local Authority Building Control during the project.

From experience, we’ve found that addressing approvals early prevents many of the delays that homeowners worry about.

Hidden costs homeowners often miss

One of the most valuable lessons from working on conversion projects is that homeowners often focus only on construction costs.

What actually tends to increase budgets are:

• Electrical upgrades
• Floor levelling
• Heating installation
• Additional storage requirements
• Decorative finishes

We’ve found that setting aside a contingency budget of around 10% helps manage these unexpected items without disrupting the project.

How long does a garage conversion take?

Less puts a typical single garage conversion at two to four weeks, and four to six weeks where it adds a bathroom or kitchen, structural work or a high specification finish.

Simple conversions can be completed relatively quickly because the structure already exists. Projects involving bathrooms, structural alterations, or significant upgrades may take longer.

From working with clients, we’ve found that the projects completed most efficiently are those where design decisions and material selections are finalised before construction begins.

Real-world insight from conversion projects

From completing conversion projects across Kent, one detail many homeowners do not expect is how much the finished room changes the flow of the entire property.

Sarah Ramsden, one of our customers, wrote in a Google review that "Alex also converted our garage into a study/ snug where again his workmanship was at the highest quality."

That kind of practical outcome is difficult to predict from drawings alone but becomes obvious once the space is being used daily.

Conclusion

The typical garage conversion cost ranges from about £6,000 to £25,000 or more, depending on the size, specification, and intended use of the space. For many homeowners, it represents one of the most cost effective ways to gain additional living space without extending the property.

From working with clients throughout Kent, we’ve found that well-planned garage conversions consistently deliver strong value, improved functionality, and greater enjoyment of the home. You can see conversion and renovation projects in our work from across Kent. If you are considering converting your garage and would like practical advice on costs and possibilities, you can contact us to discuss your plans. At AGC Carpentry & Building Services, the focus is on practical design, quality workmanship, and conversions that genuinely improve how homes are used.