If you have searched “how much does an architect cost” you have probably found percentage fees, hourly rates and stage fees that are hard to compare. This guide gives our indicative fixed fees for the planning and Building Regulations stages by project type, explains what pushes a fee up or down, and lists the third-party costs that sit outside any designer’s fee so you can budget the whole thing.
A note on who we are: Magna Studio are architectural designers, not architects registered with the Architects Registration Board (ARB), so we do not use that title. Planning, Lawful Development Certificate and Building Regulations drawings do not legally require a registered architect; the drawings, the process and the council’s decision are the same whoever prepares them. The fees below are our own bands as architectural designers.
How are design fees charged in London?
There are three common models, and the model matters as much as the number:
- Percentage of construction cost. Traditional for full-service appointments, typically quoted as a share of the build budget across every stage. The fee rises if the build gets more expensive, which is the wrong incentive on a project with a clear brief, and you do not know the figure until the build is priced.
- Hourly or day rate. Common for small pieces of advice and for feasibility work. Fine for a defined hour of advice, hard to budget for a whole planning stage.
- Fixed fee per stage. A stated figure for the planning stage and another for the Building Regulations stage, agreed before any work starts, with the scope and the number of revision rounds written down. This is how we quote.
How much do planning drawings cost by project type?
Our planning-stage fee covers the measured survey, existing and proposed drawings to the council’s validation checklist, the planning route advice, any statement the route needs, submission through the Planning Portal and acting as your agent until the decision. For a medium-sized London home the indicative bands are:
| Project | Indicative planning-stage fee (excl. VAT) |
|---|---|
| Single-storey rear or side extension | £1,900–£2,500 |
| Wraparound (rear and side) extension | £2,800–£3,500 |
| Two-storey extension | £3,000–£3,800 |
| Loft conversion with rear dormer | £2,000–£2,600 |
| Hip-to-gable loft with rear dormer | £2,200–£2,800 |
| Mansard loft | £2,800–£3,400 |
| Outbuilding, garden room or annexe | £1,300–£1,700 |
| Internal alterations only | £1,100–£1,500 |
These bands are indicative and rounded to the nearest £50; your written quote is the fixed figure. Smaller projects sit below the band and larger ones above it. For loft-specific detail see how much an architect costs for a loft conversion; for extensions see how much an architect costs for a house extension.
How much does the Building Regulations package add?
A Building Regulations package typically adds 110–140% of the planning fee. For a rear extension quoted at £2,200 for planning, expect roughly £2,400–£3,100 for the construction drawings and specification. The package covers structure (coordinated with your engineer’s calculations), thermal performance, fire, ventilation, drainage and the details building control checks, and it takes 3–5 weeks. It can start while the council is deciding the planning application.
A full package, adding a concept stage before planning and tender-ready details after Building Regulations, typically adds a further 35–55% on top of the two stages together. Most London extensions and lofts do not need it; the two stages above are what you need to obtain consent and get comparable builder quotes.
What makes the fee higher or lower?
- Size. A 25 m² kitchen extension and a 45 m² wraparound are different amounts of drawing, so each band has a small, medium and large figure.
- Planning route. A Lawful Development Certificate for permitted development is quicker to prepare than a full planning application, which needs a design statement and often negotiation with the case officer.
- Heritage status. A conservation area adds a modest uplift, typically around 15%, because the design has to answer the character appraisal and usually a published design guide. A listed building adds around 30%, because listed building consent needs a heritage statement and far more detail.
- Property type. Flats and maisonettes carry roughly a 10% uplift: they have no permitted development rights, the freeholder’s consent is usually needed and fire strategy involves the whole building. Detached houses carry around 5% for the extra elevations and roof.
- Previous extensions. Anything added since the house was built counts against the permitted development allowance, so the assessment takes longer and the project more often needs full planning.
What is included in a fixed fee, and what is never included?
Included in our planning-stage fee: the measured survey, existing and proposed plans, elevations and sections, the site location and block plans, the planning route assessment, any Design and Access, heritage or permitted development statement the route requires, submission, validation queries, one round of revisions after your review and correspondence with the case officer until the decision. The written proposal lists every drawing by name.
Never included, because they are paid to other people: VAT; the council’s application fee (£528 for a householder application, £264 for a proposed-use Lawful Development Certificate in England from April 2025, verify before applying); building control charges; the structural engineer; a party wall surveyor; and specialist reports such as arboricultural, flood risk, daylight and sunlight or heritage assessments. We tell you which of these your project needs before you commit and list each in the proposal with a typical range. For the whole budget, council fee to builder, see how much planning permission costs in London.
Do fees include VAT?
No. Fees on this site and in our quotes are the practice fee excluding VAT, which is added at the prevailing rate. Council application fees do not attract VAT. Your written quote shows the fee, the VAT and the total so a comparison with another quote is straightforward.
How many revisions are included?
Each quote states the number of revision rounds at each stage, so you know before you start. Adjustments to a design within the agreed brief are part of the fee. A change to the brief itself, such as adding a storey or switching from a dormer to a mansard, is a scope change, and we quote for it in writing before doing the work. The fee does not change unless you change the scope.
How do I compare quotes fairly?
Ask each practice for the same five things and put them side by side:
- The fee for the planning stage and, separately, for the Building Regulations stage, each excluding VAT.
- Whether the measured survey is included or a separate charge.
- The list of drawings and documents each stage delivers.
- The number of revision rounds included, and what counts as a scope change.
- Who acts as agent with the council, and whether that continues until the decision.
A low headline fee with the survey, the statements and the agent role stripped out is usually the more expensive option once those are added back.
How long does each stage take?
- Measured survey booked within 1 week of instruction.
- Planning or LDC drawings issued 2–3 weeks after the survey.
- Submission within 2 working days of your sign-off.
- Council decision: 8 weeks from validation for both a householder application and an LDC.
- Building Regulations package: 3–5 weeks.
How do I get my own figure?
Answer six questions in the quote tool and an indicative fee for your project arrives on screen and by email in two minutes. A written fixed-fee quote follows within 24 hours of a short conversation about the property. We work across every London borough and the towns around the capital, from Hackney and Croydon to Sevenoaks and St Albans, on the same fee bands.
Related guides and services
- How much does planning permission cost in London?: the whole budget, council fee to building control.
- How much does an architect cost for a house extension?
- How much does an architect cost for a loft conversion?
- Architectural designer vs architect: which you need and why the title matters.
- Planning documentation and Building Regulations drawings.
