If you run an interior studio in India, the single field that quietly causes the most invoice trouble is the little code you put next to each line, because you know a code belongs there, you are just not sure which one, and whether design uses the same kind of code as a sofa. That confusion is where clean invoices go to die, because a wrong code invites your client's accountant to send the bill back, and a payment you were counting on stalls for two weeks over a number. So let me walk through HSN and SAC codes for interior design services in plain language, the numbers most studios use, the mistakes that trip people up, and how to keep it clean without calling your CA every single time.
SAC for services, HSN for goods, and why that split matters
Start with the one distinction that clears up half the confusion. HSN codes, the Harmonized System of Nomenclature, are for goods, physical things you supply like furniture, tiles or lighting. SAC codes, Services Accounting Codes, are for services, like your design work itself. Same idea, different family, and the reason it matters for interiors specifically is that your invoices are almost always a mix of the two, some service, some goods, and each side carries its own code and often its own rate.
That mixed nature is the whole reason interior invoicing feels harder than it should, and it is also why you cannot just put one code at the top and hope it covers everything. If you want the ground-up version of raising the invoice itself, I wrote it in how to raise a GST-compliant invoice for design work, and this piece zooms in on the codes.
The SAC code for interior design work
Here are the numbers most studios actually use. For interior design and decoration services, the SAC sits under 9954 at the broad level, with the more specific code being 995443 for interior decoration and design services. If your practice also does architectural work, architectural services sit under 9983, with 998321 covering architectural advisory and design. You can confirm any of these against an HSN and SAC code lookup or the official lists on the CBIC-GST site, which is worth bookmarking.
The practical bit is this. If you only supply the design consultancy, you use the service SAC and charge GST on it as a service. But the moment you start supplying furniture, modular units or finishes as part of the deal, those goods carry their own HSN codes, and you cannot fold them into the design SAC. I dug into the rate side of this in the GST rate on interior design services in India, which pairs naturally with this one.
A quick map of the codes you will actually touch
Here is a rough map of the codes an interior studio bumps into. Treat the goods rates as a prompt to confirm rather than gospel, because rates on goods do shift and depend on the exact item, but the structure is what you want to internalise.
| What you are billing | Code family | Typical code | Notes |
|---|---|---|---|
| Interior design and decoration | SAC | 995443 | Under the 9954 group |
| Architectural design and advisory | SAC | 998321 | Under the 9983 group |
| Wooden and modular furniture | HSN | Chapter 94 | Confirm the exact item rate |
| Lighting fittings | HSN | Chapter 94 | Confirm the exact item rate |
| Ceramic tiles and sanitaryware | HSN | Chapter 69 | Confirm the exact item rate |
| Turnkey fit-out, design plus execution | SAC | Works-contract service | Depends on contract structure |
The last row is the one that genuinely depends on how your contract is written, so it is the place I would confirm with your CA rather than guess.
The mistakes that get invoices bounced
Let me be honest about where studios slip, because these are the same three every time.
The first is putting an HSN code on a service line, or a SAC on a goods line, which is a small mix-up that immediately flags an invoice as sloppy. The second is using one code for the whole invoice when the invoice is clearly a mix of design and supplied goods, which understates or overstates tax and confuses the client's input credit. The third is leaving the code off entirely on some lines, usually the ones typed in a hurry at the end of the day, which technically makes it an incomplete tax invoice.
Get your codes clean before the invoice goes out
- Use SAC 995443 for interior design lines, or 998321 for architectural design
- Put an HSN code on every supplied-goods line, never a SAC
- Split design and goods onto separate lines, each with its own code and rate
- Confirm any goods rate against a code lookup if you are unsure
- Never leave a code blank on a taxable line
- Keep the same codes flowing from your spec through to the invoice, so nothing is re-typed
How the codes should carry themselves
Here is my honest take after watching too many studios lose evenings to this. The codes are the least creative thing on the invoice, so they should not be typed fresh every time, they should flow. When you spec a project room by room, the design line already knows it is a service and the furniture line already knows it is a good, so by the time an approved quote becomes a GST invoice, the SAC and HSN codes carry through on their own, which is exactly how we built it into the connected workflow I described in how to turn a quote into a GST invoice in minutes. That is also the deeper point of running one connected workspace rather than five apps, laid out in why one connected system beats five disconnected tools, because when the codes live with the specs, they cannot go missing at invoice time.
For the money side of keeping this tidy across the year, from codes to input credit to filing, the basics are in bookkeeping basics for an interior studio, and if you are choosing a tool to run all of it, the best software for interior designers in India guide covers the practice-management side. When in doubt on a specific code or rate, the official GST portal is the source of truth.
The bottom line
HSN and SAC codes stop being scary once you hold the one distinction, SAC for your design service and HSN for anything you physically supply, and once you accept that an interior invoice is usually a mix that needs both. Use 995443 for interior design, put the right HSN on each goods line, split them cleanly, and never leave a code blank, and your client's accountant relaxes instead of sending the bill back.
The better move is to stop typing codes by hand at all. Your studio runs on one flat founding price for the whole team, billed in rupees, with unlimited free client logins, done-for-you onboarding and data migration, and a 7-day money-back guarantee. Poke around a real setup at demo.designa.work, and when you want your codes to carry themselves from spec to compliant invoice, grab the founding offer at go.designa.work.
Frequently asked questions
What is the SAC code for interior design services in India?
Interior design and decoration services sit under SAC 9954 at the broad level, with 995443 as the specific code most studios use, while architectural design and advisory sits under 9983 with 998321.
Do I use HSN or SAC on an interior invoice?
Both, because interior invoices are usually mixed, so you use a SAC code like 995443 on design service lines and an HSN code on every line where you supply physical goods such as furniture, tiles or lighting.
What is the difference between HSN and SAC codes?
HSN codes classify goods and SAC codes classify services, so the code family you use on a line depends on whether that line is a physical item you supply or a service you perform.
What is the most common coding mistake studios make?
Using one code for a whole invoice that mixes design and supplied goods, or putting a SAC on a goods line and an HSN on a service line, both of which flag the invoice and can hold up the client's input credit.