Charging a flat fee means you quote one fixed price for a clearly defined scope of interior design services—regardless of how long it takes. This model works best when scope is tight and expectations are clear.
Below is a practical, professional method designers use.
Step 1: Define the Scope Precisely (Non-Negotiable)
A flat fee only works if scope is locked. Clearly specify:
Spaces covered
- Full home / selected rooms
- Carpet area (sq ft)
Deliverables
- Space planning & layouts
- Number of 3D views per room
- Working drawings (carpentry, electrical, ceiling)
- Material & finish selection
- Vendor coordination (yes/no)
- Site visits / supervision (yes/no)
Revisions
- Number of revisions included (e.g., 2 rounds)
- Cost of extra revisions
Flat fee = fixed scope. Any scope change = change order.
Step 2: Choose a Flat-Fee Calculation Method
Method A: Convert Per-Sq-Ft to Flat Fee (Most Reliable)
- Decide your per-sq-ft design rate
- Design only: ₹120–₹250 / sq ft
- Design + supervision: ₹250–₹400 / sq ft
- Multiply by carpet area
Flat Fee = Area × Rate
Example (3BHK):
- Area: 1,200 sq ft
- Rate: ₹200 / sq ft
👉 Flat fee = ₹2,40,000
Round it to a clean number (₹2.4L or ₹2.5L).
Method B: Percentage → Flat Fee Conversion
- Estimate interior execution budget
- Apply a standard percentage
- Design only: 6–10%
- Design + supervision: 10–15%
- Convert to a fixed amount
Example
- Execution budget: ₹15 lakh
- Design fee @10% = ₹1.5 lakh
👉 Quote ₹1.5 lakh flat
Use this when project size is predictable.
Method C: Room-Wise Flat Fee (Partial Projects)
Charge per room and bundle.
Typical flat ranges:
- Living room: ₹40,000 – ₹90,000
- Bedroom: ₹30,000 – ₹70,000
- Kitchen: ₹50,000 – ₹1,20,000
Example
- Living + 3 bedrooms + kitchen
👉 ₹2.0 – ₹2.8 lakh flat
Step 3: Set Flat-Fee Benchmarks (India)
| Project Type | Reasonable Flat Fee |
|---|---|
| 1BHK | ₹60,000 – ₹1.2 lakh |
| 2BHK | ₹1.0 – ₹2.0 lakh |
| 3BHK | ₹1.5 – ₹3.0 lakh |
| Villa / Large Home | ₹3 – ₹6 lakh+ |
(Design only; supervision is extra unless specified.)
Step 4: Structure the Payment Milestones
Never take 100% upfront.
Recommended split
- 30% — Onboarding & concept
- 40% — 3D designs approved
- 20% — Working drawings
- 10% — Final handover
This protects both sides.
Step 5: Add Clear Exclusions (Critical)
Always list what’s not included:
- Extra site visits beyond limit
- Civil/structural drawings
- Vendor procurement & payments
- Revisions beyond agreed rounds
- Changes after sign-off
State hourly or per-revision charges for extras.
Step 6: Put It in Writing (Short Contract)
Your agreement should include:
- Scope & deliverables
- Flat fee amount
- Payment milestones
- Timeline
- Revision policy
- Termination clause
Flat fee without a contract = disputes.
Pros & Cons of Flat Fee
Pros
- Predictable income
- Easy for clients to understand
- No billing disputes
Cons
- Scope creep risk
- Not ideal for undefined or evolving projects
When Flat Fee Works Best
- Apartments (2–3BHK)
- Design-only services
- Clear client brief
- Limited customization
Avoid flat fees for open-ended renovations or luxury villas unless scope is frozen.
Bottom Line
To charge a flat fee:
- Lock scope
- Base fee on sq ft, % conversion, or room-wise logic
- Quote ₹1.5–3 lakh for a typical 3BHK
- Protect yourself with milestones and exclusions
If you want, tell me:
- Flat size
- City
- Design only or with supervision
I can help you price a flat-fee proposal correctly.