GST Invoice Format: How Goods and Services Invoices Differ

The short answer: the core Rule 46 fields apply to both goods and services invoices, but several details genuinely differ — the classification code, the quantity field, how place of supply is determined, and whether an e-way bill is needed. Picking the wrong "type" in a billing tool isn't just cosmetic; it changes which fields get validated and how tax is calculated.

What classification code does each use?

Goods are classified with an HSN (Harmonized System of Nomenclature) code. Services are classified with a SAC (Services Accounting Code), which sits under Chapter 99 of the same broader coding system. Both exist for the same reason: to pin down exactly what's being sold so the correct GST rate can be applied consistently. See our HSN & SAC codes guide for how many digits your invoices actually need based on turnover.

Why does the quantity field behave differently?

Rule 46 requires quantity and unit (or a Unique Quantity Code) for goods — it makes sense to record "10 units" or "5 kg" on a goods invoice. Services generally don't have a meaningful physical quantity in the same way; a design project, a consulting hour block, or a software subscription is typically priced as a single line item or a rate rather than a countable unit. In practice, this field is left blank or simply not shown for a pure service line.

Does place of supply work differently for goods versus services?

Yes, and this matters because place of supply is what determines whether you charge CGST+SGST or IGST (see our CGST vs SGST vs IGST guide for the full mechanics). For most goods, place of supply is typically the location where the goods are delivered. For most services, it's typically the location of the recipient. Both have documented exceptions — for goods, certain transactions involving assembly/installation at a site follow different rules; for services, categories like those tied to immovable property follow the property's location instead. When in doubt on an unusual transaction, confirm the exact rule on the GST portal.

Does the time of supply differ too?

Broadly, yes. Time of supply is the point at which GST liability arises. For goods, this is generally tied to removal or delivery, or the invoice date, whichever is earlier under the applicable rule. For services, it's generally tied to the invoice date or the date payment is received, whichever comes first in the applicable scenario. The practical difference is usually small for straightforward transactions, but it's worth knowing these aren't identical rules borrowed from the goods side.

Do services invoices need an e-way bill?

No. E-way bills exist to track the physical movement of goods above a certain value threshold — since nothing physically moves with a pure service, e-way bill requirements simply don't apply. This is one of the cleanest goods-vs-services distinctions: if you're only invoicing a service, you can skip this requirement entirely.

Goods invoice vs services invoice, side by side

The practical takeaway

When you're creating an invoice, correctly choosing "goods" or "services" — or entering the right code type for each line item — isn't a formality. It changes which fields should be validated, how the place of supply (and therefore the CGST/SGST vs IGST split) is worked out, and whether extra requirements like e-way bills apply. Mixed invoices with both goods and service line items are common — a product sale that includes an installation fee, for example — and each line should be classified on its own terms rather than forcing the whole invoice into one category. For the full walkthrough of building a compliant invoice from scratch, see our step-by-step guide to creating a GST invoice.

QWIK INVOICE's invoice builder lets you add an HSN or SAC code per line item, so you can mix goods and services correctly on the same invoice without losing track of which classification rule applies to which line.