Garage conversion cost

Checkatrade puts a typical garage conversion at £10,000 to £20,000, with an average of £15,000. MyJobQuote gives an average of £14,500 within a much wider range of £8,000 to £45,000, and the Federation of Master Builders (FMB), quoting its member Fittra Construction, gives £7,000 to £32,000, with most projects averaging £13,500 for a standard 16m² garage. FMB's house renovation page gives a single figure of £13,000.

The type of garage makes the biggest difference, because a garage built into the house needs far less work than a separate building. The table shows each source's figures by garage type in separate rows. No source gives Sussex prices, though MyJobQuote says London and the South East run 15 to 25% above the national average.

Checkatrade heads its table "Cost + VAT", which does not make clear whether VAT is already included or should be added, and MyJobQuote and FMB do not say either way. MyJobQuote also gives a single garage range of £8,000 to £20,000 in one part of its page against the £45,000 upper figure in its headline, so treat the widest ranges with care. Ask each builder to show VAT as a separate line so you can compare quotes properly.

What you turn the garage into matters as much as the garage itself. A home office needs little more than insulation, heating, lighting and sockets, while a bedroom with an en suite needs plumbing, drainage, ventilation and tiling. MyJobQuote's figures for a single garage show how quickly the price climbs as the room becomes more serviced.

Checkatrade gives figures for adding wet rooms or a kitchen on top of the basic conversion. It says a bathroom adds £5,500 to £9,000 and a kitchen adds £15,000 to £35,000, which can more than double the price of a simple conversion. If you are unsure which use you want, ask builders to price the basic conversion and the bathroom or kitchen separately.

There is no single answer that fits every home, so check with your local planning authority before you start. Permitted development rights for householders apply to houses, not to flats and maisonettes, according to the Planning Portal, and a council can remove those rights through an Article 4 Direction, as GOV.UK's householder technical guidance explains. Some homes also have a planning condition that restricts changes, so check your property's planning history as well.

If the conversion involves extending the building or changing its outward appearance, the extension rules apply, and the Planning Portal says materials should be of similar appearance to the existing house. Listed buildings need listed building consent for alterations that would affect their character, and the Planning Portal warns that carrying out such work without consent beforehand is a criminal offence. Conservation areas can also bring extra controls, so ask your council what applies to your street.

If you need a planning application, GOV.UK gives the householder fee in England as £548 from 1 April 2026. If you believe the work does not need permission and want that confirmed in writing, you can apply for a lawful development certificate for a proposed use, which the Planning Portal says costs half the normal planning fee, with a decision within 8 weeks. Our extension planning permission guide explains permitted development in more detail, but no one can guarantee that an application will be approved.

Give every builder the same brief, including the use of the room, the position of any new window or door, and whether you want a bathroom or kitchen. Ask for an itemised quote that shows the front wall, floor, insulation, electrics, heating and finishes separately, and check whether drawings, structural calculations and building control are included or left for you to arrange. Confirm whether the price includes VAT and how the work will be staged and paid for.

Comparing at least three prices is the best way to see whether a quote is in line with the published figures for your type of garage. Sussex Builder can put you in touch with up to 3 checked local builders for free, no obligation quotes, through our garage conversion page or by calling 01273 115520. If you are also thinking about wider work on the house, our house renovation cost guide sets out published prices for rewiring, replastering, kitchens and bathrooms.