Work out a ballpark build cost from floor size, spec level and the extras you want. Every rate below is editable, so you can drop in a real quote and recalculate.
Size
Internal floor area updates automatically below.
Build spec (editable rate per m²)
Extras (editable costs)
Many garden room companies quote prices inclusive of VAT. Tick this only if your rates above are VAT-exclusive.
How this works and what to assume
The base figure is floor area (width × depth) multiplied by the per-m² rate for your chosen spec. The default rates are typical UK ranges for a supplied-and-fitted garden room and are only a starting point. Real prices vary by builder, region, glazing area, roof type and ground conditions.
Extras are added as flat amounts on top. Groundwork cost depends heavily on access and whether the ground is level. The electrical figure assumes a qualified electrician runs an armoured cable from your consumer unit and notifies Building Control under Part P.
Replace any default with a number from a real quote to make the estimate accurate. This tool gives an indicative budget, not a fixed price or a quotation.