Is your interior design practice profitable? Effective hourly rate, utilisation and overhead

How do you tell whether an interior design practice is profitable?

Busy is not profitable. Profit is what remains after all costs, including paying yourself a market salary. The fastest practical test is to compare two numbers per project: your effective hourly rate and your cost per hour. Last reviewed: 30 October 2026.

How do you calculate your effective hourly rate? A worked example

All figures here are fictional and for illustration. A solo designer agrees a fixed design fee of $12,000. Hours logged across the project:

Effective hourly rate = $12,000 / 170 = $70.59. If the designer's standard rate is $120, realisation is 70.59 / 120 = 58.8%. The studio earned about 59 cents for every dollar of its price list.

Now add product mark-up. The client buys $40,000 of furnishings at cost, marked up 25% on cost, which earns $10,000 (a 20% margin on the $50,000 selling price). Total revenue earned is $22,000 for the same 170 hours, an effective rate of $22,000 / 170 = $129.41. The product margin rescued a design fee that, alone, was too low. That is only true if the procurement hours are counted, as they are here.

• Mark-up and retainer tracking

How do you calculate your break-even hourly rate?

Break-even rate = (target salary + annual overhead) / annual billable hours. Fictional solo designer: target salary $72,000, overhead $36,000 (software, insurance, workspace, marketing, accountant). That is $108,000 of costs to cover.

Available time: 46 weeks x 40 hours = 1,840 hours. At 60% utilisation, billable hours are 1,104. Break-even rate = $108,000 / 1,104 = $97.83 an hour. To earn a 15% profit above costs, revenue needed is $108,000 x 1.15 = $124,200, so the rate is $124,200 / 1,104 = $112.50.

Utilisation matters. At 75%, billable hours are 1,380, and the same $124,200 needs only $90.00 an hour. The cost of a low utilisation rate is paid in price.

The example project above earned an effective $70.59 on its design fee alone, below the $97.83 break-even. Product mark-up lifted the project over it. Without that mark-up, the project loses money.

What benchmarks exist, and how far can you trust them?

Some vendor-run blogs, including financial-model sellers, quote ranges for net margin, utilisation and overhead for interior design firms. We have not verified any of them against primary data, and they are written by sites that sell models or software, so treat them as rough prompts only.

Your own history is a better benchmark: this year versus last year, fixed-fee projects versus hourly projects, small versus large.

How do you track time without hating it?

You need time data to know anything above. Keep it light.

• Log in five to ten categories (discovery, concept, development, procurement, site, admin), not in minutes of activity.
• Log at the end of each day in a single pass; memory fades by the next morning.
• Log time on fixed-fee jobs too; that is where you learn what the fee really paid.
• Include unbilled time such as long emails and unscheduled calls. They are the hours realisation hides.
• Review each finished project: planned hours, actual hours, effective rate. Put the result into your next proposal.

A simple rule for improving estimates: after five projects of a type, set the estimate at the average actual hours, not the plan.

What do you do when the numbers say you are not profitable?

• Scope creep and change orders
• Pricing models compared
• Studio KPIs (architecture, applies in principle)

Where InteriorDesignOS fits

We make InteriorDesignOS, a Notion template, so weigh our view accordingly. InteriorDesignOS is a $39 one-time Notion template. Projects record construction value and amount invoiced, and Fees & Invoices holds your fee information, so you can see what you agreed against what you billed. It does not log time automatically, compute utilisation or replace accounting; add a hours property by hand if you want actual hours beside fees.

• InteriorDesignOS
• Pricing
• Run the whole practice

Frequently asked questions

What is an effective hourly rate for an interior designer?

It is the fee earned on a project divided by every hour spent on it, billed or not. A $12,000 fee over 170 total hours is $70.59 an hour, which may be well below your listed rate. It shows what the project really paid.

How do I calculate my break-even hourly rate?

Add your target salary and annual overhead, then divide by billable hours for the year. With $108,000 of costs and 1,104 billable hours the break-even is $97.83. Those numbers are an example; use your own figures.

What is a good utilisation rate for a design studio?

No verified benchmark is available. Vendor blogs quote ranges, but treat them as unverified. Measure billable divided by available hours and watch the trend. In our example, raising utilisation from 60% to 75% cuts the required rate from $112.50 to $90.

How much profit should an interior design firm make?

There is no reliable, verified figure; published ranges come from vendors and vary widely. Calculate your own net margin as revenue minus all costs, including a market salary for you, divided by revenue, and track it by project type.

Does product mark-up count toward profitability?

Yes, as revenue, but count the hours spent sourcing, ordering and chasing as well. If procurement takes 36 hours, the mark-up has to cover those hours before it adds to profit.