Interior Designer Fees Explained: Hourly, Fixed, Percentage & Cost-Plus

Two designers quote for the same London flat. One sends a single number for the whole job. The other quotes an hourly rate, then mentions a markup on furniture, then something about a percentage of your build budget. Both are normal. The problem is that they look nothing alike, so you cannot tell which is cheaper, or which is fairer to you.

This guide breaks down the four ways interior designers actually charge, what each one costs in the UK and in London, and the parts most cost guides skip: how trade discounts and procurement markups work, whether VAT lands on top, and how to read two very different quotes side by side.

Most quotes are a blend, not one clean model

Before the four structures, one fact reframes everything. The British Institute of Interior Design (BIID) surveyed its members on how they bill, and the split was:

• Combination of methods: 51%
• Fixed fee: 21%
• Hourly: 18%
• Percentage of project cost: 6%

So the single most common answer is “a bit of several.” Pure percentage billing, the model many guides present as one of four equal options, is actually used by roughly one designer in sixteen. A real quote usually mixes a fixed design fee with hourly rates for extra work and a markup or fee on anything they buy for you. You can read the BIID’s own breakdown on its How to price a project page.

The same survey points to why the market feels so opaque: around 80% of designers do not publish their fees at all. That is the gap this article fills. The numbers below are honest, cross-checked ranges, not invented quotes; treat them as a sense of scale, then ask any designer to confirm their own.

1. Hourly rate

You pay for the time the designer spends, usually with time tracking, billed by the hour or day.

This suits work where nobody can predict the scope yet: a consultation, a one-room layout, help choosing materials, or advice on a brief that is still vague. You only pay for the hours used.

Indicative UK ranges:

• The BIID survey on senior designers put most at up to £75 an hour (59% of respondents), with the rest in the £76 to £150 band (41%).
• Across the broader market, junior or regional designers sit lower, while mid-level designers in cities such as Edinburgh, Manchester or Bristol charge more.
• London and high-end work runs higher again, often well into three figures an hour. Some London consultation rates quoted are far steeper, but those headline “initial consultation” figures are a ceiling, not a typical ongoing rate. Do not assume the peak number is what you will pay per hour all the way through.

Pros: fair when the scope is genuinely unknown, flexible, and you only pay for time used.

Cons: open-ended and hard to budget. An indecisive client can rack up hours, and you have to trust the time logs.

Best for: small jobs, a single-room refresh, advice-only sessions, and briefs that are not yet defined.

2. Fixed or flat project fee

One agreed price for a defined schedule of works: concept, layouts, specification and material schedules, and a set list of deliverables.

This is the model the Society of British and International Interior Design (SBID) recommends, and it is the easiest to budget against. The trade-off, as BIID notes, is that the designer carries the risk: if the work overruns, that is their problem, not your bill, which is why a careful designer prices in a small buffer.

Indicative ranges: a full design for a single room typically lands in the low thousands, with lighter “package” pricing for a more limited scope. In central London, at the experienced end, a single-room project fee starts considerably higher. For contrast, online “e-design” packages, where you receive a scheme to execute yourself, are a fraction of full-service fees; a real, currently advertised example is My Bespoke Room, which offers room design, room styling and quick “design fix” packages at clearly listed online prices.

Pros: maximum transparency. You know the number before work starts, with no surprise invoices.

Cons: anything outside the agreed schedule is handled as a change order, so be clear about what is in and what is out. The risk buffer can make it look pricier on paper than an hourly quote that later overruns.

Best for: well-defined briefs, single rooms, and anyone who simply wants a known figure.

3. Percentage of project cost

The design fee is set as a percentage of the total project budget, usually the combined construction and furnishing (FF&E) spend. If you have worked with an architect, this will feel familiar, because architects bill the same way.

Indicative ranges genuinely vary by source, so treat this as a band rather than a single number. In the BIID survey, just over half of those using percentage billing charged 6 to 10%, with smaller groups higher. Commonly cited bands run from around 8 to 15%, and wider quotes stretch lower or higher depending on project size. As a worked example, a £120,000 project at 10% gives a £12,000 design fee.

Pros: it scales with complexity, it is intuitive on a combined build-and-design job, and it is familiar from architecture.

Cons: the obvious criticism is the conflict of interest. If the fee rises with the spend, does a bigger budget serve you or the designer? A good designer addresses this head on; a vague one hopes you will not ask. It is also hard to quote accurately early, before the real scope is known.

Best for: large renovations and new builds, especially projects running alongside an architect or main contractor.

4. Cost-plus (markup on goods and procurement)

This is the structure most UK cost guides leave out, and it is often where the real money sits. It governs what happens when the designer buys things for you.

Designers can access trade pricing that the public cannot: fabric houses, bespoke joinery, specialist lighting, furniture suppliers. Trade discounts typically run from around 10 to 40% off retail, with most mainstream programmes landing in the 20 to 30% range. Under cost-plus, the designer buys at that trade price and then charges either the trade price plus a procurement or management fee, or a figure closer to retail while keeping the trade margin.

SBID gives useful, authoritative guidance here. For a “design plus product supply” arrangement, it points to a procurement administration fee of around 15% on commercial work, and a 15% discount off retail on residential work. Importantly, SBID discourages designers who keep the trade discount and charge no design fee at all, warning that clients then risk getting “products where best discounts are available rather than the most appropriate.” In other words, free design is not free; it just hides the cost inside what you buy. SBID sets out its three fee models on its Design Fees page.

The transparency point is the one to hold onto. There are three honest ways a designer can handle a trade discount: pass it to you, keep it, or split it (for example, a 20% discount split ten and ten). None is automatically wrong. What matters is that the contract states clearly whether trade pricing is passed through, retained, or shared. The well-known criticism that “cost-plus isn’t always cheaper than retail” is true precisely when the markup is not disclosed.

Pros: you get access to trade-only suppliers you could never buy from directly, and SBID notes the savings can exceed the design fee itself.

Cons: if the markup is hidden, the conflict of interest is real and the price opaque.

Best for: design-heavy, furniture-heavy projects where sourcing is most of the value.

Design fee versus procurement: the distinction that catches people out

Two different things often sit on one invoice. The design fee pays for thinking: the scheme, the drawings, the specifications, the decisions. Procurement is the buying and managing of goods: ordering, tracking, coordinating deliveries, handling returns. A designer might charge a fixed design fee and then a separate procurement fee or markup on everything purchased. When you compare quotes, separate these two in your head, because one quote may bundle them and another may split them out.

Do interior designers charge VAT?

If a designer is VAT-registered, yes, and it changes the bill materially. According to the BIID, VAT applies both to the design fee and to goods bought on your behalf. So a quoted fee may be before VAT, and furniture the designer procures for you can carry VAT on top too.

Registration is not optional above a threshold. A business must register for VAT once its taxable turnover passes the limit, which is £90,000 for the 2026/27 year, unchanged since April 2024 (see gov.uk’s VAT registration guidance). A smaller sole-trader designer below that threshold may not charge VAT at all, which is one reason two quotes can differ by a fifth before any design even happens. Always ask whether a quote is inclusive or exclusive of VAT.

London versus the rest of the UK

London consistently runs above the national average, commonly by something in the order of 30 to 50% more, across hourly rates, fixed fees and per-room pricing alike. Central, high-end studios sit at the top of every band in this guide. If you are weighing London-specific numbers, our interior designer cost in London breakdown and the 2026 update go deeper on local figures, and the interior designer fees UK page sets the national baseline for comparison.

How to compare two very different quotes

Because 51% of designers blend methods, you will rarely compare like with like. Put both quotes against the same checklist:

1. Deliverables. What exactly do you receive: drawings, schedules, visuals, a shopping list, site visits? List them out for each quote.
2. What is in and what is out. A low fixed fee covering less is not cheaper.
3. Change-order policy. What happens, and at what rate, when the brief shifts?
4. Who handles procurement, and is there a separate fee or markup for it?
5. Trade pricing. Is the trade discount passed to you, kept, or split? Get the answer in writing.
6. VAT. Inclusive or exclusive, on the fee and on goods.

A designer who answers all six plainly is showing you how they work. One who deflects on trade pricing and VAT is the one to press hardest. When you are ready to brief studios, our guide to hiring an interior designer in London walks through the steps.

Frequently asked questions

Do interior designers pass on their trade discount or keep it? It depends on the designer, and there is no single rule. Some pass the full trade discount to you, some keep it as part of their compensation, and some split it. SBID warns against designers who keep the discount and charge no design fee, because that can quietly steer you toward whatever is most discounted rather than what is right. Ask the question directly and get the answer written into the contract.

Is a percentage fee a conflict of interest? It can be, and it is fair to raise it. Because the fee rises with your total spend, a percentage model gives the designer a financial reason to favour a bigger budget. That does not make it dishonest; it is standard practice, the same way architects charge. A trustworthy designer will explain why the percentage is justified for your project and will be comfortable being asked.

What is the difference between the design fee and procurement? The design fee pays for the creative and technical work: the scheme, drawings and specifications. Procurement is the separate job of sourcing, ordering and managing the goods. A designer may charge for them separately, with a design fee plus a procurement fee or markup, so check whether a quote bundles them or splits them out.

Hourly or fixed fee, which is safer for me? A fixed fee gives you budget certainty, which suits a well-defined brief where you want to know the number up front. Hourly is fairer when the scope is genuinely unclear, since you only pay for time used, but it is open-ended and harder to control. For a small, vague job, hourly often works; for a defined room, a fixed fee usually feels safer.

Why won’t designers publish their prices? Roughly 80% do not, according to the BIID. Every project differs in scope, location and how goods are sourced, so a single published number would mislead more often than it helps. It is frustrating as a buyer, but it is why asking for an itemised, written quote against the checklist above matters so much.

Does the fee include VAT? Not necessarily. A VAT-registered designer charges VAT on both the design fee and goods bought on your behalf, while a smaller designer below the registration threshold may not charge it at all. That difference alone can move a quote by a fifth, so always confirm whether the figures are inclusive or exclusive of VAT.