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GST · 25 June 2026

7 Fields Every Skilled Professional Must Put on a GST Invoice: Rule 46 Checklist

A GST-registered skilled professional, an electrician, plumber, carpenter, tailor, mechanic, AC technician, painter, or fabricator, must issue a tax invoice under Section 31 of the CGST Act carrying the particulars listed in Rule 46. Seven fields are the ones trades most often miss: their own GSTIN, a unique invoice number, the invoice date, the SAC code for the service, the taxable value with the CGST/SGST or IGST split, the place of supply for the job, and, only if the work is exported, the LUT reference or a payment-of-IGST note. Each is a hard requirement, and a missing field costs the client input tax credit.

In this section
Myth

A plumber, electrician, or tailor can bill a job on a plain estimate slip with a name, the work, and an amount.

Fact

A GST-registered tradesperson must raise a tax invoice carrying the Rule 46 fields, or the client cannot claim input tax credit and the bill fails at audit.

What must a skilled professional put on a GST invoice?

Short answer

A GST-registered tradesperson issues a tax invoice under Section 31 carrying the Rule 46 particulars. Seven of those fields are the ones an electrician, plumber, carpenter, or tailor most often misses.

  • Rule 46 lists every field. For a service job the goods-specific entries (quantity, unit of goods) fall away, leaving a tighter set for a labour-and-materials bill.
  • If your turnover is below the registration threshold and you are unregistered, you issue a bill of supply, not a tax invoice, and most of this list does not apply.
  • Why it matters: under Section 16(2)(a) a contractor or business client claims input tax credit only against a valid invoice, so a missing field is your client's lost credit.

The 7 fields, in order

Short answer

GSTIN, invoice number, date, SAC code, taxable value with the tax split, place of supply, and the export note. Each maps to a Rule 46 clause.

#FieldWhat a tradesperson gets wrong
1Your GSTINLeaving it off the bill. Your 15-character GSTIN must appear as the supplier on every job invoice.
2Invoice numberA unique, consecutive serial up to 16 characters for the financial year. Starting a fresh count for each client breaks Rule 46(b).
3Invoice dateMust follow the time-of-supply rules; dating a bill back to when the job started, not when it billed, is an audit flag.
4SAC code for the serviceService Accounting Code, not an HSN. An AC technician, electrician, or fabricator uses the SAC for the service, e.g. 9954-series for construction and installation work.
5Taxable value + tax splitShow the taxable value, the rate, and CGST + SGST for a same-state job or IGST for an out-of-state job.
6Place of supplyFor on-site work this is usually where the job is done. Bill a client in another state and it becomes IGST.
7Export noteOnly if the service is exported: a Letter of Undertaking (LUT) reference for supply without IGST, or a "with payment of IGST" note. Most local trades skip this.

Source: Rule 46, CGST Rules 2017. SAC = Service Accounting Code; LUT = Letter of Undertaking under Rule 96A. SAC/HSN digit requirements vary by turnover tier, so check your tier before finalising a template.

Why the SAC code and place of supply trip up trades

Short answer

The SAC code fixes your GST rate, and the place of supply decides whether you charge CGST/SGST or IGST. Get either wrong and the tax on the bill is wrong.

  • SAC, not HSN: a plumber, electrician, or painter supplies a service, so the bill carries a Service Accounting Code, not the HSN code used for goods. The code drives the rate, so a guess can understate GST.
  • Place of supply for on-site work: for a job at the client's premises, the place of supply is usually that location. Same state means CGST + SGST; another state means IGST.
  • Materials plus labour: when you supply parts and fit them on one bill, it is generally a single service of works contract or installation. One SAC and one place-of-supply still govern the invoice.

When does the export note apply to me?

Short answer

Only if you supply a service to a client outside India. Then the supply is a zero-rated export under the LUT route (Rule 96A) or with payment of IGST. A local tradesperson billing Indian clients never needs it.

  • Most skilled-trades work, fitting, repair, tailoring, fabrication, is supplied to clients in India, so field 7 stays blank and the in-state CGST/SGST or out-of-state IGST split is all you need.
  • A design or fabrication professional billing a foreign client is the exception: that supply is a zero-rated export and the invoice must show the LUT reference or the IGST-payment note.
  • Why it matters: putting an export note on a local bill, or leaving it off a genuine export, is the field that turns a clean invoice into a queried one.