Interior design fees are determined by four factors: the scope of work (full scheme or single rooms), your property’s size and complexity, the specification level you choose (materials, bespoke elements, finishes), and the design studio’s approach to the process. Rather than a fixed hourly or percentage rate, most studios cost based on the depth of work required across Discovery, Concept, Design & Specification, Commission, and Reveal.
Why interior design doesn’t have a simple per-room price
Interior design pricing appears opaque because no two projects are identical. A small apartment bedroom in London requires different exploration than a commercial salon across multiple floors. The London Embankment Apartment and the Witham Project are both residential but demanded entirely different scope, timeline, and specification decisions. One studio’s approach to costing reflects the actual work involved: research, multiple design iterations, specification of materials and finishes, liaison with contractors, and site management through completion.
Many prospective clients expect a cost per square metre or a percentage of build budget. These methods fail because they don’t account for the intellectual and project-management work that happens before a single order is placed. A 40-square-metre space requiring bespoke joinery, custom lighting design, and material sourcing involves substantially more design hours than the same space furnished with standard-specification pieces. The studio’s process — Discovery, Concept, Design & Specification, Commission, Reveal — is structured to explore complexity early so costs are understood before commitment.
How project scope shapes what you’ll invest
Scope is the most direct cost driver. Are you redesigning one room or an entire property? Is the work residential or commercial? Beaulieu Dental Practice, Fruittii Hair Salon, and Keystones Estate Agent are all commercial projects but with distinct spatial demands, user flows, and brand expression requirements. Each demanded a different intensity of design and specification work. A single living room refresh costs less than a full-scheme residential overhaul because the Discovery and Concept phases are narrower, fewer contractors need coordination, and the Reveal involves fewer moving parts.
Commercial projects typically extend scope further: they require understanding how staff move through space, how clients experience arrival, how finishes perform under higher footfall. A salon like Fruittii demands different material choices than a dental practice or estate agency. Residential work, by contrast, often focuses on how inhabitants live day-to-day: how spaces connect, how light moves, how materials age. The scope question — what rooms, what use, what stakeholders — should be clarified in the Discovery phase before any fee is discussed.
What property size and condition contribute to cost
Larger properties cost more to design, primarily because more surfaces, more rooms, and more connections between spaces require more decisions and specification. A 200-square-metre London apartment involves more design work than a 100-square-metre flat. But size alone is misleading: a property in poor condition, or one with structural or logistical constraints, can demand more design problem-solving than a larger, simpler space. Witham Project and the London Embankment Apartment are both residential but likely had different cost implications based on their existing conditions, local supply chains, and site access.
Renovation projects typically cost more to design than new-build interiors because the designer must work within existing constraints: ceiling heights, service runs, structural walls, dated layouts. A designer must explore solutions across multiple iterations before the Concept is locked. Properties requiring specialist trades — bespoke carpentry, conservation work, or high-specification finishes — add design hours because material sourcing, craftsperson liaison, and site supervision increase. The property’s location also affects cost indirectly: London projects like Tone at Canary Wharf and the London Embankment Apartment often involve longer lead times, specialist suppliers, and more complex logistics than regional work.
How specification level — the choices you make — drives investment
Specification level is what most people underestimate when budgeting. This means: how bespoke are the pieces? How many custom elements (joinery, lighting, finishes) versus off-the-shelf items? How durable and refined do materials need to be? A scheme using standard plasterboard, contractor’s paint, and high-street furniture requires less design specification work than one specifying bespoke joinery, natural stone, artisan plasters, and commissioned lighting. The studio’s role expands considerably when specification rises: sourcing becomes more complex, approval processes lengthen, and site supervision deepens.
Quiet luxury — the studio’s approach — typically involves higher specification because restraint and permanence demand careful material choice. A palette of three paint colours and one natural stone takes more design thought than a scheme with six colours and mixed finishes. Bespoke joinery that lasts thirty years costs more upfront than flat-pack alternatives but is a different project entirely. The Reveal stage confirms whether the specification decisions made during Concept, Design & Specification have translated to reality. Projects that prioritise longevity and restraint generally require more careful specification, which affects the design fee proportionally.
How the studio’s process structure affects what you pay
A transparent design process lets you understand what work drives cost. Discovery — research, site visits, user interviews, constraint mapping — is where the studio uncovers what actually needs designing. Concept is where big moves are tested: layout, material direction, spatial hierarchy. Concept, Design & Specification is the detailed work: every finish named, every dimension locked, every supplier identified. Commission is the studio’s site liaison as work happens. Reveal is the handover and final sign-off. Each phase has real cost implications because each requires time, expertise, and often external consultation (structural engineers, conservation specialists, lighting designers).
Studios that charge by the hour or a simple percentage miss this structure — they front-load cost assumptions. Studios that cost per phase allow you to understand where your investment goes and where you can be flexible. Some clients may choose to skip Commission phase support if budgets tighten; others may invest heavily in Discovery to avoid costly revisions later. The process names and stages are fixed, but how intensively each is pursued depends on your scope, property, and specification level. Understanding this structure helps you make realistic budget decisions before work begins.
What to discuss at your first consultation
When you approach a studio, bring clarity on these points: What rooms or spaces are in scope? Is the work residential or commercial, new-build or renovation? What condition is the property in, and are there known constraints (listed building, structural issues, access problems)? What specification level appeals to you: are you investing in bespoke elements and longevity, or seeking a cost-conscious refresh? How soon do you need completion, and do you need the studio to manage contractors (Commission phase) or just deliver drawings? These conversations belong in Discovery, and they determine not just cost but whether the studio is the right fit.
Avoid studios that quote a fee before understanding your project. Cost should follow scope, not precede it. A consultation should feel like genuine exploration: the studio asking questions, listening to how you use space, understanding your priorities. This is where you learn whether a studio’s approach — its process, its values, its track record — matches what you need. Book a consultation with Manong to discuss your project in detail. We work through Discovery to understand what your space truly needs before any numbers are discussed.