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How to Create a GST-Compliant Invoice for Interior Projects

Jun 16, 20263 min read
How to Create a GST-Compliant Invoice for Interior Projects

How to Create a GST-Compliant Invoice for Interior Projects

A non-compliant invoice is worse than no invoice — your client cannot claim input tax credit, will hold payment, and you face penalty risk. This is the exact step-by-step to issue a GST-compliant tax invoice for an interior project in India.

Step 1: Confirm the trigger

You issue a tax invoice when:

  • A milestone is hit (advance, dispatch, installation, handover).
  • A service is delivered (design fee, supervision sign-off).
  • Goods leave your premises.

Issue within 30 days of service completion. For goods, at the time of removal/dispatch.

Step 2: Pick the invoice number

The invoice number must be:

  • Unique within the financial year.
  • Sequential — no gaps.
  • Max 16 characters, alphanumeric, plus / and -.

Format example: INT/2026-27/0042.

Never edit a number after issuing. If you cancel, issue a credit note (not a number reuse).

Step 3: Identify Place of Supply

  • Installation work: site address state.
  • Pure design (delivered remotely): client's registered address.
  • Goods dispatched to site: site address state.

This determines CGST+SGST vs IGST. Get it wrong and your client cannot claim ITC.

Step 4: Build the line items

Each row needs:

  • Description with specification.
  • HSN (for goods) or SAC (for services).
  • Quantity and unit.
  • Rate.
  • Taxable value.
  • Tax rate.

See GST rates for interior work for codes.

Step 5: Compute taxes correctly

  • Intra-state: Taxable value × 9% = CGST; same × 9% = SGST.
  • Inter-state: Taxable value × 18% = IGST.

Round at the row level, then sum. Some accountants prefer rounding only at totals — pick one rule and apply consistently.

Step 6: Include the mandatory header block

  • Your name, address, GSTIN, PAN.
  • Recipient name, address, GSTIN.
  • Place of supply with state code.
  • Reverse charge applicability.
  • Invoice date.
  • Subtotal, discount, taxable value, tax breakup, grand total.
  • Amount in words.
  • Bank details (for direct transfer).
  • Terms (payment due, late fees).
  • Authorised signatory.

Step 8: Generate the PDF and share

Save as PDF with a clean filename: INT-2026-27-0042-ClientName.pdf. Email plus WhatsApp link.

Step 9: Record in your books

Update your GST register the same day. At month end, your GSTR-1 should pull directly from this register — no last-minute typing.

Step 10: Hold the cancellation discipline

If you must cancel, issue a credit note referencing the original invoice number. Never delete or renumber.

Where designers go wrong

  • Reusing draft invoice numbers. Audit failure.
  • Place of supply = client billing address for site work. ITC denied.
  • Bundled tax shown only at footer, no per-row split. Client cannot reconcile.
  • No digital signature on the PDF. Corporate clients reject.

Doing it in 60 seconds with software

The 10 steps above collapse to a single conversion in Intorza:

  • Convert approved quotation → tax invoice.
  • Confirm milestone.
  • Hit Generate.

GSTIN, HSN/SAC, place-of-supply logic, sequential numbering, and signing are all automatic.

Start free →

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