Garden room cost calculator
Set the size and the extras to see what a built, insulated garden room usually costs in and around Chesterfield. The plan on the right is drawn to scale.
By Garden Rooms Chesterfield. Prices checked October 2026.
Free matching service, not a building firm. We find you a local garden room builder. How it works
Typical built price
£19,000 to £24,000
12.0 m² inside the walls, before rounding
Grid squares are 1 m. The rust line marks the doors.
Insulated, double glazed, wired and fitted. A typical range, not a quote.
Get a fixed priceGarden room prices by size
Before extras, rounded to the nearest £500. Small standard models can start from about £10,000.
| Size | Floor area | Typical price |
|---|---|---|
| 2.5 × 2.5 m | 6.25 m² | £10,000 to £12,500 |
| 3 × 2.5 m | 7.5 m² | £12,000 to £15,000 |
| 3.5 × 3 m | 10.5 m² | £17,000 to £21,000 |
| 4 × 3 m | 12 m² | £19,000 to £24,000 |
| 5 × 3 m | 15 m² | £24,000 to £30,000 |
| 5 × 4 m | 20 m² | £32,000 to £40,000 |
| 6 × 4 m | 24 m² | £38,500 to £48,000 |
| 7 × 4 m | 28 m² | £45,000 to £56,000 |
Extras and what they add
Added to the base price above.
| Extra | Typical addition |
|---|---|
| Toilet or shower room | £4,000 to £8,000 |
| Bifold doors in place of sliding doors | £1,500 to £3,000 |
| Air conditioning (heats and cools) | £1,500 to £3,000 |
| Slope, awkward access or extra groundwork | £1,000 to £3,000 |
Where these prices come from
The base range of £1,600 to £2,000 per square metre comes from prices that garden room builders across north Derbyshire and South Yorkshire publish, read in October 2026. We found no reliable figures for Chesterfield alone, so these are regional prices.
The extras were checked on 25 October 2026 against national guides: the MyBuilder garden room cost guide, MyJobQuote's garden room costs, Summerhouse24's guide to rooms with a shower and toilet, and AirCon Adviser's guide to air conditioning in garden rooms. These national guides put a 12 m² room at roughly £18,000 to £24,000, in line with the regional range.
Treat the result as a budget guide. A builder gives a fixed price after a visit, because the ground, the access and the length of the cable run all change the cost. If planning permission might be needed, read how big you can build without it first.
Cost questions
How accurate is a garden room cost calculator?
It is as good as the prices behind it. Ours uses £1,600 to £2,000 per m², from what builders in the region publish, plus national guide prices for extras. Your own garden, access and specification decide the real figure.
What is included in the price per square metre?
An insulated floor, walls and roof, double glazed doors and windows, an electrical supply from the house with lights and sockets, cladding, and fitting. Furniture, a bathroom and heavy groundwork are extra.
Why do small garden rooms cost more per square metre?
Doors, glazing, the electrics and the site visit cost roughly the same whatever the size, so they make up a bigger share of a small room. A room twice as big rarely costs twice as much.
Is a pitched roof more expensive?
Usually a little, because of the extra timber and roofing. Ask for both options if you are unsure. Our roof guide compares them.
How do I get a fixed price?
A garden room builder visits, measures the spot, checks the ground and the cable route, and prices your exact room in writing. Our form gets you that visit, free.
Do I pay VAT on top?
Builders publish prices both ways. Ask whether a quote includes VAT, so you compare like with like.
Turn the estimate into a fixed price
Three steps: where, what and who. It takes a couple of minutes, and a little detail now saves a lot of back and forth later.
This is a free matching service, not a building firm. We find a garden room builder near you and name them to you first. Nobody calls you until you say yes.
Thanks, your enquiry is in.
- Within one working day we will email or call to tell you which garden room builder covers your area.
- Your details reach that firm only if you say yes.
- They visit, look at the spot and give you a fixed price. No marketing from us, ever.