Guide · Billing
GST invoicing for architects and interior designers in India
What belongs on an architectural services invoice, and the handful of fields that cause most of the disputes.
8 min read · Updated 5 September 2026
What a tax invoice must carry
Professional-services invoices fail audit for boring reasons, not exotic ones — a missing place of supply, a client GSTIN typed from memory, an invoice number that repeats across financial years. The fields below are the ones a design practice is most often asked to produce later.
- Your legal name, address and GSTIN, exactly as registered.
- A serial invoice number that is unique and unbroken for the financial year.
- Date of issue, and the period or milestone the fee covers.
- Client legal name, address and GSTIN (or a note that the client is unregistered).
- Place of supply, with the state name and code.
- Description of service, SAC code, taxable value, tax rate and tax amount split by head.
- Whether tax is payable on reverse charge.
- Signature or digital signature of the supplier or an authorised person.
Statutory details in this guide reflect the position as of September 2026. Rates and thresholds change — confirm with your CA before you rely on them for a filing.
Classifying the service correctly
Architectural and interior design fees are professional services, not works contracts, and are normally classified under the 9983 architectural/engineering services family; 9971 covers financial and related services and is the wrong home for a design fee. The distinction matters most when your scope mixes design with supply or execution.
| What you actually did | Treat it as | Watch out for |
|---|---|---|
| Design, drawings, tender documents, site supervision | Professional / architectural service | Keep the fee separate from any material supply |
| Design plus procurement of furniture or fittings | Two lines: service and goods | Goods carry their own HSN and rate |
| Turnkey interiors including execution | Likely a works contract | Different classification and often different rate |
| Reimbursed printing, travel, statutory fees | Pure agent recovery, if conditions are met | Needs supporting documents in the client's name |
If a single engagement contains more than one of these, split the invoice into lines rather than averaging a rate across the whole fee. A blended rate is the single most common reason a design invoice gets reopened.
Place of supply: the CGST/SGST vs IGST decision
For services relating to immovable property — which is most of what an architecture practice does — the place of supply follows the location of the property, not the location of the client's office. A Bengaluru studio designing a house in Kerala for a Bengaluru client is not automatically an intra-state supply.
- 01Identify the site the work relates to, not the address on the client's letterhead.
- 02Compare that state with your own place of registration.
- 03Same state: charge CGST and SGST. Different state: charge IGST.
- 04Record the state code on the invoice so the return matches later.
Consultancy that is not tied to a specific property — feasibility advice, brand or product design — follows the general place-of-supply rule instead. Ask which one applies before the first invoice, not at the end of the project.
Advances, stage fees and retention
Design fees rarely arrive in one piece. The three shapes below each behave differently, and mixing them up is what makes a practice's books disagree with its bank.
| Shape | What it is | Practical handling |
|---|---|---|
| Mobilisation advance | Money before work | Adjust it against later stage invoices; keep the running balance visible |
| Stage fee | A percentage on completing a stage | Invoice on stage sign-off, not on calendar month |
| Retention | A slice held back until completion | Bill it, track it as receivable, and chase it — it is the most commonly forgotten money in a practice |
Retention is the reason so many studios feel poorer than their revenue suggests. It is invoiced income that has never landed, and unless something is counting it separately from ordinary overdue receivables, nobody chases it.
TDS: why the client pays you less than the invoice
Corporate clients typically deduct tax at source on professional fees before paying. The deduction is against your income tax, not lost money, but it does mean the bank credit will not match the invoice. Reconcile receipts against invoices with the deduction recorded, or every payment looks short.
- Record the gross invoice, the deduction and the net receipt as three separate figures.
- Collect the deduction certificate each quarter rather than at year end.
- Reconcile against your annual tax credit statement before filing.
How UpLabs handles this
UpLabs raises invoices from the project rather than from a blank form: the stage, the fee schedule and the client's registration details are already attached, so the classification and place-of-supply fields are filled from what the project already knows. Retention is tracked as its own balance rather than mixed into ordinary receivables, and every invoice stays exportable.
Common questions
- Do I need to register for GST as a small practice?
- Registration is driven by turnover thresholds and by whether you make inter-state supplies. Because architectural work frequently crosses state lines, many small practices register earlier than the turnover alone would require. Confirm your position with your CA.
- Can I invoice in a foreign currency for an overseas client?
- Yes, and the supply may qualify as an export of services if the conditions are met, including receipt in convertible foreign exchange. The documentation requirements are stricter than for domestic work.
- Should reimbursements be part of the fee invoice?
- Keep them on separate lines at minimum. Recoveries that meet the pure-agent conditions are treated differently from fees, and merging them into a single fee line removes your ability to show that later.