Interior Design Project Budgets: How to Plan, Control, and Stay Profitable
A practical guide to budgeting an interior design project — from contingency reserves to real-time spend tracking. Why Excel breaks on large projects.
Dora Team
Why budgeting is the weakest link
Most designers work confidently with concept, visualization, and product selection. But when the client asks three months in, "why has the budget grown by 30%?", few can answer precisely. The reason is that the budget is usually kept as a list of prices, not as a living control instrument.
Below are the principles that help keep a budget under control from the first sketch to the final invoice.
Separate "hard" and "soft" costs
Hard costs — items with a fixed price: furniture, plumbing, appliances, lighting. The price here is known at the moment of ordering.
Soft costs — anything calculated by linear meter, square meter, or hour: finishing materials, labor, delivery, installation. Prices here fluctuate: area measurements are refined, scope changes, extra operations appear.
Track these two categories separately. 80% of budget overruns sit in soft costs, and mixing them with hard costs hides the real picture.
Plan a 10–15% contingency reserve
No project is executed at the original budget. Common reasons:
- Currency fluctuations on imported items
- Supplier price increases between approval and order
- Additional work discovered on site
- Replacing discontinued products with more expensive alternatives
- Logistics, customs, upstairs delivery
10–15% of the total budget is not over-insurance — it is a realistic baseline. A client who is warned about the contingency upfront does not perceive actual spending as your error.
Account for currency
If part of the specification is imported, record both the item's currency and the exchange rate used at pricing time. When the order date arrives, you immediately see the delta — and can either pass it to the client or absorb it from the contingency.
Keep "planned in local currency" and "actual in local currency" as separate columns. The difference is your signal that the budget is moving in the wrong direction.
Track planned vs actual in real time
A budget reviewed once a month is not a budget — it is a report. Control works when, after every order or payment, you immediately see the updated total and the deviation from plan.
In Excel this is manual, with a high risk of broken formulas on large projects. In specialized platforms (Dora, Programa, Studio Designer) every paid item automatically moves to "actual," and the variance is calculated without your involvement.
Communicate changes to the client immediately
The biggest mistake is accumulating changes for a month and showing the client a "+18%" total at the end. It looks like you have lost control.
The right practice: as soon as you learn that an item will cost more than planned, tell the client along with options. "The Italian sofa went up 12% due to exchange rates. Options: keep this model, switch to a local equivalent at the original price, or consider a different brand altogether." Clients dislike surprises — but they respect being offered a choice.
Track your fee and margin separately
A common mistake is bundling your design fee into a "design" line item and dissolving it in the total. Keep your own compensation separate: project fee, supervision percentage, procurement margin (if you work with one). This makes it transparent how much you earn on the project and helps you avoid eating your own margin when the client pushes to reduce cost.
Do a final reconciliation before closing
Before handing over the project, reconcile:
- Planned vs actual by category
- Contingency used
- Amounts the client paid vs amounts you paid suppliers
- Your final earnings
This is not bureaucracy — it is the only way to know whether the project was actually profitable. Without this step you can run unprofitable projects for years without noticing.
Conclusion
A budget is not a table of prices. It is a risk management tool. Splitting hard and soft costs, a contingency reserve, currency accounting, real-time plan-vs-actual tracking, and a transparent fee — together these turn the budget from a source of stress into a working mechanism.
A project where you control the budget closes with the expected profit. A project without control closes with a random one.