How Is an Interior Design Fee Calculated? The Factors That Determine the Price

The information in this article applies to Turkey. If you're asking how much interior design costs and expecting a clean price per square metre, you get half the answer. The Chamber's minimum fee calculation starts from the area of the space, but the real quote is set by which service sections you request and how detailed the space is.

Area is where the calculation starts, not where it ends

Like an architecture fee, the Chamber of Interior Architects' minimum fee formula starts from area: the approximate area of the space is multiplied by the unit cost the Ministry publishes for that year^[2]; the result is then multiplied by the project and tender documentation (PİD) ratio, the service-section ratio and a coordination coefficient of 1.4 that applies across Turkey^[1]. The difference lies in how the service is divided. The Chamber splits interior design into five sections: survey 10%, preliminary design 20%, final design and material selection 30%, working drawings and fabrication details 35%, and room schedules, quantities and work programme 5%^[1]. Someone asking only for a preliminary design and someone asking for everything down to the fabrication details pay very different fees for the same area. On top of that, 100 m² of one space and 100 m² of another can demand very different amounts of work depending on how intensively they are used; that decides the difference above the minimum fee.

What actually determines the price

• Scope of service: Do you want only a concept and material palette, or a turnkey process running from furniture selection through execution follow-up? The wider the scope, the higher the fee.
• How intensively the space is used: A bedroom and a kitchen or wet area carry a different level of detail even at the same square footage; commercial spaces (café, store, office) generally demand more technical detail than residential ones.
• Number of 3D visualizations: Requesting a separate photorealistic render for every space is more work than a single overall visualization.
• Material/furniture procurement follow-up: Are you only getting the design, or are we also following the purchasing and execution process for materials and furniture?

The minimum fee: the Chamber of Interior Architects' schedule

The Chamber of Interior Architects publishes its minimum fees based on the Ministry's unit costs for that year; the 2026 fees were published with the 2026 unit costs^[1]. Still, "my home is 120 m², how much will it be?" has no single answer: a figure given before it is clear which service sections are included is either a very rough estimate or gets revised later.

How the process works at MEEZ Mimarlık

On the Elif Perde store project we designed and built in Yomra, we clarified the scope (storefront concept, circulation, lighting) from the start, which let the project stay true to its planned budget and timeline. At our first meeting, we work through your space, which areas it will cover, and the level of detail you're requesting, and then present a written quote based on that.