Every supply under GST has to be classified — goods using HSN codes and services using SAC codes. These codes are not just paperwork: they drive the rate that applies, what you report on invoices and in returns, and how consistently your supplies are described across the system. Using the wrong code can mean charging the wrong rate or facing mismatches later. Here's what HSN and SAC codes are and how to use them.
Reviewed by CA Harika Chebolu, FCA · Last updated 2026-06-15
Quick answer
HSN codes classify goods and SAC codes classify services under GST. Here's what they are, where they go on your invoices and returns, and why they matter.
HSN stands for the Harmonised System of Nomenclature, an internationally recognised system for classifying goods, while SAC refers to the Service Accounting Codes used to classify services. Under GST, goods are described using HSN codes and services using SAC codes, giving every supply a standard classification. This shared language makes it possible to apply rates consistently and to match supplies across invoices, returns and the wider system. Think of the code as the identity tag for what you are supplying.
The classification code is closely tied to the rate of tax that applies to a supply, so picking the right code is not a clerical detail — it can change how much GST you charge. An incorrect code can lead to applying the wrong rate, which creates exposure if you have undercharged and customer friction if you have overcharged. It can also cause mismatches when your reporting is compared against others in the chain. Because correct classification underpins the correct rate, it is worth getting the code right at the outset rather than fixing it later.
HSN and SAC codes appear on your tax invoices and flow through into your GST returns, where supplies are reported by their classification. Showing the appropriate code on the invoice tells the customer and the system exactly what is being supplied and supports the rate charged. The level of detail required in the code can depend on factors such as the nature and scale of the business, and these requirements can change. Because of that, confirm the level of detail that applies to you rather than assuming a single approach fits every business.
Classifying a supply is not always obvious — similar-sounding goods or services can fall under different codes, and bundled or composite supplies need careful thought about what is really being supplied. The aim is to describe the supply accurately and consistently, using the same classification for the same supply each time. Keep a record of how you have classified your main supplies so that your invoices and returns stay consistent. Where a supply is genuinely ambiguous, it is better to resolve the classification deliberately than to guess.
Consistency is the practical goal. Classify each supply correctly once, apply the same HSN or SAC code every time you make it, and ensure the code on the invoice matches what flows into your returns. This reduces rate errors and the mismatches that can surface when reporting is reconciled across the chain. Review your classifications periodically, especially when requirements change or you introduce new products or services. When you are unsure which code or level of detail applies, get it confirmed before it becomes a recurring error.
HSN codes classify goods and SAC codes classify services, giving every supply a standard classification under GST. This shared language lets rates be applied consistently and supplies to be matched across invoices and returns.
Because the code is closely tied to the rate of tax that applies, so the wrong code can mean charging the wrong rate. An incorrect classification creates exposure if you undercharge, friction if you overcharge, and mismatches when reporting is compared across the chain.
Yes — HSN and SAC codes appear on tax invoices and flow into your returns, and the level of detail required can depend on factors such as the nature and scale of your business. Confirm the level that applies to you rather than assuming one approach fits every business.
Not sure which HSN or SAC code your supplies fall under? Write to the firm and we'll help you classify them correctly and keep your invoices and returns consistent.