How long an interior design project takes: real timelines by stage

How long an interior design project takes on average — the short answer

For a property of around 100 m² with prompt approvals, an interior design project takes about 2.5 months — from the first meeting and site measurements to the handover of technical documentation. This period covers the technical brief, the concept design with layout and visualisation, and the technical documentation for the building team; the furnishing schedule is compiled in parallel and finalised after the drawings are handed over. This is a benchmark drawn from the studio's practice, not a universal formula: below is the timeline for each stage and what it actually depends on.

Timeline by stage

The technical brief is the first substantive stage: measurements, an assessment of the building services, zoning, and a concept with references. For a property of around 100 m² it takes roughly two weeks and ends with a signed document set that fixes the brief for all the following stages.

The concept design is the stage with the most decisions: it settles the layout, the spatial geometry, and the final visualisation with lighting. A typical property takes 20 working days or more; this is the stage where the furniture arrangement and the look of the interior can still be adjusted easily, so rushing it works against the project.

Technical documentation translates the approved design into drawings, details and specifications for the building team — a further 20 working days or so. The furnishing schedule does not wait for the final stage: it starts back at the technical brief and is finalised roughly a week after the technical documentation is handed over.

Here is what this timeline looks like in practice, on a space-planning project for a developer, a separate and shorter type of work than a full interior design project: it started on 25 April 2025 and was handed over on 30 May. Within that month there were checkpoints of its own: on 5 May the target-audience profile was agreed, on 6–7 May the DWG base plan was reviewed and the measured survey was carried out, and from 12 to 20 May the draft layouts were developed. On projects with a partial redesign, the schedule is distributed differently: for example, in one apartment the main work was scheduled for handover in early September, with the decor finished afterwards.

Why the range is wider than the average figure

The figures above are a benchmark for a property of around 100 m² and a typical level of design complexity. In practice, the range by stage is noticeably wider: the initial concept with references takes 5 to 15 working days, visualisation 15 to 40, and technical documentation 10 to 63. The spread is driven not only by square metres but also by style: elaborate styles with a lot of non-standard furniture, decor and bespoke details stretch out the concept design stage and the technical documentation far more than extra floor area on its own.

What actually shifts the timeline

The size of the property is not the main lever that moves the schedule. The stages of an interior design project run sequentially: the layout is not started until the technical brief is signed off, and the technical documentation is not started until the visualisation is approved. Because of this sequence, a delay in the client's response at any stage shifts not just that stage but the whole remaining schedule. Prompt approvals are not a box-ticking exercise; they are the only real way to keep a project at the lower end of the range rather than the upper end.

How the project timeline relates to the renovation timeline

The interior design project timeline is the time before construction starts, not a substitute for it: the technical documentation, which takes up most of the cycle, is precisely the document that later governs the sequence of the renovation without on-site improvisation. A project fully worked out in drawings over 2.5 months usually saves time on site: changes are made on paper in hours rather than on site over weeks. A detailed breakdown of all seven steps of the process, from the first meeting to handover for construction, is in the article ‘Stages of an interior design project: from measurement to construction’.

How to get a timeline estimate for your own property

Average figures give a general idea, but the exact timeline depends on the specific floor area, layout and chosen style. The fastest way to estimate the schedule for your own property is at a consultation with a designer: that is also where you can discuss which elements of the chosen style can realistically fit the lower end of the range and which will need time closer to the upper end.

For more on what a full interior design project includes and how it compares to a renovation without one, see the article ‘Interior design project: the complete breakdown’.