In short: drawing up plans for a home project in the UK usually costs between £1,000 and £5,000+, depending on the size of the job and whether you need planning drawings only or a full set that includes building regulations. Small extensions sit at the lower end; loft conversions and larger two-storey projects sit higher. This guide breaks down what you should expect to pay in 2026, how architects charge, and how a fixed-price service compares with the traditional percentage-of-build-cost model.
Typical architect drawing costs at a glance
| Project type | Planning drawings | Full plans (planning + building regs) |
|---|---|---|
| Single-storey extension | £1,000–£2,500 | £2,500–£5,000 |
| Loft conversion | £1,200–£2,500 | £2,500–£4,500 |
| Two-storey extension | £1,500–£3,000 | £4,000–£6,000 |
| New build home | £2,500–£5,000+ | £4,000–£8,000+ |
These are the drawings only. You’ll also budget separately for your council’s planning application fee (typically £300–£700, paid directly to the council) and, if your project needs one, a structural engineer (typically £700–£2,000).
Fixed price vs percentage of build cost
How you’re charged matters as much as the headline number. There are three common models in the UK:
- Percentage of build cost — a traditional architect often charges around 7–15% of your total build cost for a full service. On a £60,000 extension that’s roughly £4,200–£9,000, and because it’s a percentage, the fee rises as the build gets more expensive.
- Hourly rate — commonly £50–£100 per hour. Flexible for small pieces of work, but the final bill is hard to predict up front.
- Fixed fee — one agreed price for a defined set of drawings, so you know the cost before work begins.
Here’s how the traditional model compares with Arkiplan’s fixed-price approach:
| Traditional architect | Arkiplan | |
|---|---|---|
| How you’re charged | Often 7–15% of build cost, or £50–£100/hr | One fixed price, confirmed in writing before any work starts |
| Cost certainty | Can move as the build cost or hours change | Known to the pound, up front |
| Paying for it | Usually staged fees | Pay up front or across 3 monthly instalments, no interest, no credit checks |
| Typical saving | — | £2,284 saved on average vs traditional architects |
The point isn’t that one is always cheaper — it’s that a fixed price removes the guesswork. With a percentage or hourly arrangement, the number you’re quoted at the start and the number you pay at the end can be quite different.
What affects the cost of your plans
Two projects that look similar can be priced differently. The main factors are:
- Size and complexity — more floor area, structural changes or an awkward site all add drawing time.
- Which drawings you need — planning drawings show the design and layout for your application; building regulations drawings add the technical detail a builder works from. A full set covers both and costs more than planning drawings alone.
- Whether extra specialists are involved — most extensions with a new opening or a removed wall will need a structural engineer, which is a separate cost.
- The service level — drawings only sits at the lower end; a full service that also handles your council submission costs more but takes the admin off your hands.
Planning drawings vs building regulations drawings
It helps to know what each stage is for, because it’s the biggest driver of price:
Planning drawings
These are the scaled drawings that go with a planning application or a Lawful Development Certificate — existing and proposed floor plans, elevations and a site plan. They show what the finished project will look like and how it sits on the plot. If your project falls under permitted development you may not need full planning permission, but you’ll often still want a certificate to prove the work is lawful.
Building regulations drawings
These are the technical drawings your builder and building control need — construction detail, insulation, structure, drainage and fire safety. They’re more detailed than planning drawings, which is why a full set costs more than planning drawings on their own.
Do you actually need an architect to draw plans?
You don’t legally have to use a chartered architect. For most home extensions and loft conversions, an experienced architectural designer or technologist can produce everything you need for planning and building regulations, usually for less than a full architectural practice. What matters is that whoever draws your plans understands the application process and gets the technical detail right — a rejected application or a set of drawings a builder can’t work from is the expensive outcome, not the fee itself.
Arkiplan has worked this way for 18 years, with more than 2,000 homes granted permission and a 94% planning and LDC approval rate — a remote, fixed-price service designed for homeowners across England and Wales.
How to keep the cost down
- Be clear on scope early. Knowing whether you want planning drawings only or a full set avoids paying for work you don’t need yet.
- Check permitted development first. If your project qualifies, you may avoid a full planning application — though a Lawful Development Certificate is still worth having.
- Ask for a fixed price. A written fixed fee protects you from a bill that creeps up with hours or build cost.
- Get the drawings right once. Accurate plans that pass first time are cheaper than reworking a refused application.
Frequently asked questions
How much does it cost to draw plans for an extension?
For a single-storey extension, planning drawings typically cost £1,000–£2,500, and a full set including building regulations drawings is usually £2,500–£5,000. A larger two-storey extension sits higher.
Are planning drawings cheaper than building regulations drawings?
Yes. Planning drawings show the design for your application, while building regulations drawings add the technical construction detail. A full set that covers both costs more than planning drawings alone.
Do I have to pay a percentage of my build cost?
No. Percentage-of-build-cost fees are common with traditional architects, but plenty of services — including Arkiplan — work to a single fixed price agreed in writing before any work starts.
What other costs should I budget for?
Beyond the drawings, expect a council application fee (typically £300–£700, paid to the council) and, where the structure changes, a structural engineer (typically £700–£2,000).
Final thoughts
Drawing plans for a home project in the UK generally costs £1,000–£5,000+ in 2026, driven mainly by the size of the job and whether you need planning drawings, building regulations drawings, or both. The bigger decision is how you’re charged: a percentage or hourly fee can move, while a fixed price tells you exactly what you’ll pay before work begins. If you’d like that certainty, Arkiplan gives you your fixed price confirmed in writing up front, with the option to spread it across three monthly instalments — and homeowners save £2,284 on average compared with traditional architects.