What does the design cost calculator cover?

The costs that come before the build: the fees often called architect fees, for the survey and the drawings, then the structural engineer, the council's planning and building control fees, party wall surveyors, surveys and any report the council asks for. It covers houses and flats in London, with extensions, loft conversions, basements, structural changes inside and refurbishments.

Why does it ask what I want priced?

Because most people need part of it first. Choose just the design, planning permission, planning and structure, ready to build, or everything before work starts, and the price covers that choice. Everything else your project may need is listed under it, each with its own figure.

Yes. There is nothing to sign up for, and you can keep the result as a PDF report.

How accurate is the price?

It is an indicative estimate, not a quote. It works from our own design and engineering fees, the fees set by law and by the councils, and typical London fees, excluding VAT unless a line says so. Your home is priced properly after a visit.

Where can I see how each fee is worked out?

Our guide to design costs in London explains every fee, one by one, from the planning application to party wall surveyors.

Choose what you need
Needed
May be needed
Your choice

Your project will be drawn here

Start with your home

Design costs

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Design Studio · Design costs

What will the design cost?

Before a builder can price your project, it has to be designed, engineered and approved. Tell us about your home and your plans: we will build a model of your project, list the design and approvals it needs, and give an indication of what they cost in London.

Not sure of an answer? Say so. Nothing is left out: it is marked “may be needed”, with what would settle it.

01Your home

What kind of home is it?

Why we ask

Shared walls bring in the Party Wall Act, and flats have no householder permitted development rights.

When was it built?

Why we ask

HSE warns that asbestos may be in any home built or refurbished before 2000.

02Where it is

Which borough is it in?

Why we ask

Basement rules and building control charges differ by borough, and so does the Mayoral CIL band.

Is the home listed, or in a conservation area?

Tick all that apply.

Why we ask

A listed home needs consent for changes inside and out, and a conservation area or an Article 4 direction takes away some permitted development.

03Outside

What are you adding or changing outside?

Tick all that apply.

Why we ask

Outside work decides the planning route, the party wall notices and the building control charge.

04Inside

What changes inside?

Tick all that apply.

Why we ask

Structural work brings in the engineer, building control and often the neighbours.

Your design and approvals

Start with your home. Your project is modelled, noted and priced here as you answer.

Good to know

Frequently asked questions

What does the design cost calculator cover?: The costs that come before the build: the fees often called architect fees, for the survey and the drawings, then the structural engineer, the council's planning and building control fees, party wall surveyors, surveys and any report the council asks for. It covers houses and flats in London, with extensions, loft conversions, basements, structural changes inside and refurbishments.
Why does it ask what I want priced?: Because most people need part of it first. Choose just the design, planning permission, planning and structure, ready to build, or everything before work starts, and the price covers that choice. Everything else your project may need is listed under it, each with its own figure.
Is it free?: Yes. There is nothing to sign up for, and you can keep the result as a PDF report.
How accurate is the price?: It is an indicative estimate, not a quote. It works from our own design and engineering fees, the fees set by law and by the councils, and typical London fees, excluding VAT unless a line says so. Your home is priced properly after a visit.
Where can I see how each fee is worked out?: Our guide to design costs in London explains every fee, one by one, from the planning application to party wall surveyors.