Renovation Budget Calculator

Q: How much does a kitchen renovation cost in the UK?

A kitchen renovation in the UK ranges from around £5,000 for a basic refresh (new doors, worktops, appliances) to £30,000 or more for a full structural rework with high-end fittings. A mid-range kitchen for an average-sized kitchen is typically £10,000–£18,000 including supply, installation, and making good. Our calculator uses £8,000 (small), £15,000 (medium), and £25,000 (large) as mid-range benchmarks — the actual figure depends on your specification, the number of units, and whether any structural changes are needed.

Q: How much does a loft conversion cost?

Loft conversion costs vary significantly by type. A basic room-in-roof conversion (using existing roof pitch) typically costs £18,000–£28,000. A dormer conversion — which extends the roof structure to create full headroom — costs £35,000–£50,000. An L-shaped dormer on a semi-detached property can reach £55,000–£80,000. Costs include structural work, insulation, flooring, electrics, staircase, and plastering but not furniture or decoration. Planning permission is often not needed for a dormer on a rear roof slope, though building regulations approval is always required.

Q: Does a renovation add value to a property?

It depends heavily on the renovation type, the property, and the local market. Loft conversions and extensions typically add the most value — often returning more than their cost in higher-value areas. A well-executed dormer loft can add £30,000–£60,000 to a property value. Kitchen and bathroom upgrades add value but rarely match the spend pound-for-pound; buyers in a lower-price bracket may not be willing to pay for a premium kitchen. The key is whether the renovation brings the property closer to the ceiling for comparable properties in the area — going beyond that ceiling rarely pays back.

Q: Do I need planning permission for a renovation?

Many common renovations fall under Permitted Development Rights and do not require planning permission. This includes internal work, most loft conversions (rear dormers on houses), single-storey rear extensions up to 6m (detached) or 4m (attached) under the householder application, and boiler replacements. You do need planning permission for extensions exceeding PD limits, two-storey additions, front extensions, outbuildings above 2.5m in height adjacent to a boundary, and any work in a conservation area or on a listed building. Building Regulations approval is separate from planning permission and is typically required for structural work, extensions, loft conversions, and new electrical circuits — always check with your local authority before starting.

How to budget for a renovation in the UK

The most common renovation mistake is underbudgeting. Contractors quote for the work they can see; hidden problems — outdated wiring, inadequate drainage, damp behind plaster — only reveal themselves once the walls are open. A 12%–15% contingency is not pessimism: it is standard practice. Our calculator builds in 12% on top of every mid-range estimate so you start with a number you can defend, not a figure that needs rescuing halfway through.

Kitchen renovation costs in the UK

A basic kitchen refresh — replacing doors, worktops, and appliances — typically costs £4,000–£8,000. A mid-range full replacement with new units, worktops, splashback, integrated appliances, and decent flooring runs £10,000–£18,000 for a standard-sized kitchen. A high-specification kitchen with stone worktops, bespoke joinery, and premium appliances can reach £25,000–£50,000. Our benchmarks use supply-and-fit cost inclusive of tiling and making good; structural changes (moving walls, rerouting plumbing) are additional.

Loft conversion — what's involved and what it costs

A loft conversion is one of the highest-ROI projects for a UK property. The cost depends heavily on the type: a room-in-roof conversion (using the existing pitch) is the cheapest at £18,000–£28,000 but provides limited headroom unless the roof pitch is steep. A dormer conversion extends the roofline to create full headroom and a usable room; typically £35,000–£50,000. An L-shaped dormer on a semi-detached extends across both the main roof and the return, creating a large additional space; typically £50,000–£80,000. All require Building Regulations approval. Planning permission is often not needed for rear dormers under permitted development rights.

Extensions — single vs double storey

A single-storey rear extension typically costs £1,600–£2,200 per m² of new floor space, inclusive of foundations, structure, roof, insulation, glazing, internal fit-out, and making good. A 20m² extension at £1,900/m² = approximately £38,000. A double-storey extension costs slightly less per m² (£1,400–£1,800) because the structural and roofing costs are spread across two floors, but the overall project cost is higher. Extensions under 6m (detached) or 4m (semi/terraced) deep may be built under Permitted Development without a full planning application.

Renovation budget questions

How much does a kitchen renovation cost in the UK?

A basic refresh costs £4,000–£8,000. Mid-range full replacement runs £10,000–£18,000. High-specification kitchens reach £25,000–£50,000. Our calculator uses £8,000 (small), £15,000 (medium), and £25,000 (large) as mid-range supply-and-fit benchmarks.

How much does a loft conversion cost?

Room-in-roof: £18,000–£28,000. Dormer: £35,000–£50,000. L-shaped dormer: £50,000–£80,000. All require Building Regulations approval. Planning permission is often not required for rear dormers on houses under permitted development rights.

Does a renovation add value to a property?

It depends on the type and the property. Loft conversions and extensions often return more than their cost in higher-value areas. Kitchen and bathroom upgrades add value but rarely match the spend pound-for-pound at lower price points. The key is whether the renovation brings the property in line with the ceiling for comparable local properties.

Why should I budget a contingency for renovation?

Renovation projects almost always uncover unexpected costs once work begins. Hidden damp, outdated wiring, structural surprises — a 10%–15% contingency is industry standard. Our calculator applies 12% as a baseline. The contingency is not wasted if unused; it means you completed on budget.

Do I need planning permission for a renovation?

Many renovations fall under Permitted Development Rights and don't require planning permission — including most internal works, rear dormers on houses, and single-storey rear extensions within the PD limits. Building Regulations approval is separate and is typically required for structural work, extensions, loft conversions, and new electrical circuits. Always check with your local authority before starting.

Renovation Budget

How to budget for a renovation in the UK

Kitchen renovation costs in the UK

Loft conversion — what's involved and what it costs

Extensions — single vs double storey

Renovation budget questions

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