GST · 26 June 2026
What Is the UQC (Unit Quantity Code) on a GST Invoice?
A Unit Quantity Code (UQC) is a standardised, three-letter code for the unit of measurement on each line of a GST invoice and return, such as NOS for numbers, PCS for pieces, KGS for kilograms, MTR for metres, and LTR for litres. Rule 46(i) of the CGST Rules requires the quantity and its unit or UQC on a tax invoice, and the GST portal accepts only codes from its fixed list when you file the HSN-wise summary in GSTR-1 or report an e-invoice. Using a free-text unit like "pc" or "nos." instead of a listed code causes validation errors and return mismatches.
By Mr. Vihaan Jain
Last reviewed
26 June 2026
In this section
Answers
- What Is the UQC (Unit Quantity Code) on a GST Invoice?
- What Is GSTR-1, the GST Return of Outward Supplies?
- What Is GSTR-3B, the Monthly GST Summary Return?
- What Is the Time of Supply Under GST, and When Does Tax Become Due?
- Advance Receipt Under GST: When Do You Issue a Receipt Voucher?
- Credit Note vs Debit Note Under GST: When Do You Issue Each?
- What Is GSTR-2B, and Why Does It Now Decide Your Input Tax Credit?
- What Is the Value of Supply Under Section 15 of the CGST Act?
- What Are the GST Rate Slabs in India After the GST 2.0 Reform?
- Exempt vs Nil-Rated vs Zero-Rated Supply: What Is the Difference?
I can write any unit I like on an invoice line, "pieces", "pcs", "units", it is just a label.
GST returns accept only standardised Unit Quantity Codes, and they are unit-specific: numbers are NOS, pieces are PCS. Free-text variants like "pc" or "nos." fail validation and can block your GSTR-1 HSN summary.
What is the UQC on a GST invoice?
Short answer
A Unit Quantity Code is a standardised code for the unit of measurement on an invoice line, required by Rule 46(i) of the CGST Rules alongside the quantity.
When you sell 10 cartons or 5 kilograms, the number is the quantity and the unit needs a fixed code: BOX or KGS. UQC is GST's controlled vocabulary for those units, so the same goods are measured the same way across every taxpayer's returns.
- It pairs with the quantity: "50 NOS", "12 KGS", "100 MTR".
- Rule 46(i) makes the unit or its UQC a mandatory field on a tax invoice for goods.
- It is a closed list: you pick a code, you do not invent one.
Why does GST insist on standardised unit codes?
Short answer
Because returns are machine-matched. A fixed code lets the portal reconcile your GSTR-1 HSN summary and e-invoice data without ambiguity over what "unit" you meant.
If one seller writes "pc", another "pieces", and a third "no.", the system cannot total or compare them. A single code per unit makes the HSN-wise summary, the e-invoice, and the buyer's records line up automatically.
- The GSTR-1 HSN-wise summary requires a UQC for each HSN line.
- The e-invoice (IRN) schema validates the unit against the standard UQC master.
- Why it matters: a non-standard unit fails validation, so the return or e-invoice will not go through until you fix it.
Which UQC do I use for my product?
Short answer
Pick the code that matches how you sell the item. The most common are NOS for numbers, PCS for pieces, KGS for kilograms, MTR for metres, and LTR for litres.
| You sell in | Correct UQC | Common wrong entry |
|---|---|---|
| Numbers | NOS | NO, NOS., NUM |
| Pieces | PCS | PC, PCS., PIECE |
| Kilograms | KGS | KG, KILO |
| Metres | MTR | M, MTRS, METER |
| Litres | LTR | L, LIT, LTRS |
| Boxes | BOX | BOXES, BX |
| Bundles | BDL | BUNDLE, BND |
| Bags | BAG | BAGS, BG |
A working subset of the GST portal's Unit Quantity Code list; the full master carries many more codes. The left column is the unit, the middle the code GST accepts, the right the free-text entries that fail validation. Check the current portal master before relying on any single code.
What happens if I use the wrong UQC?
Short answer
A non-standard unit blocks your filing: the GSTR-1 HSN summary or the e-invoice rejects it, and you cannot proceed until you map it to a valid code.
On a paper invoice a stray "pc" looks harmless, but the moment that line enters a return it must carry a valid UQC. Getting it right at the invoice stage means you never re-key it at filing, and the buyer's records match yours.
- Validation failure: the portal or e-invoice schema rejects an unrecognised unit.
- Return mismatch: a wrong UQC can misstate quantities in your HSN summary.
- Fix it at source: set the correct UQC on the invoice line, not at filing time.
References & related
Primary sources
- Rule 46, CGST Rules 2017 — CBICRule 46(i): a tax invoice must state the quantity in case of goods and the unit or Unit Quantity Code thereof.
- GST portal — GSTR-1 and HSN summary filingThe HSN-wise summary accepts only UQCs from the portal's prescribed list.
- CBIC — GST e-invoice schema and standardsThe e-invoice (IRN) schema validates the unit field against the standard UQC master.
- Section 31, CGST Act 2017 — CBICObligation to issue a tax invoice whose contents Rule 46 prescribes.
Last reviewed: 26 June 2026