Unique Quantity Code (UQC) under GST: Meaning, List, and Common Mistakes

GST works on strict structure. Every invoice, return, and system upload follows a fixed format, and quantity is one of the mandatory details when you file your GST return.

This is where the Unique Quantity Code in GST, or UQC, comes into play.

Although it may seem minor, it is not optional. An incorrect entry can block return filings, reject invoice uploads, or trigger system errors without warning.

Understanding how UQC works helps prevent these issues before they affect compliance.

What is Unique Quantity Code

Many taxpayers still ask what is unique quantity code and why it even exists.

UQC stands for Unique Quantity Code. It is a standard unit of measurement prescribed under GST.

Instead of writing quantity in free text, GST requires a fixed code.

For example:

• 1 kilogram of rice becomes 1 KGS

• 100 metres of fabric becomes 100 MTR

• 1 litre of oil becomes 1000 MLT

These codes ensure uniform reporting across India.

No spelling differences. No local formats. One standard language for quantity.

What is UQC under GST

Under the CGST Rules, every:

• Tax invoice

• Debit note

• Credit note

must include quantity along with its UQC.

So if you sell 10 cartons of goods, the invoice should not say “10 cartons”.

It must say:

10 CTN

This rule applies regardless of your business size or turnover.

The unique quantity code in GST is mandatory wherever quantity is reported.

Where is UQC Used

UQC is not limited to invoices alone.

You must declare it in:

• E-invoicing system

• E-way bills

• HSN summary in GSTR-1

• GST offline and online return utilities

Since quantity details flow directly into GSTR-1, errors at the invoice level often surface during return filing. If you want a clearer understanding of how this data is reported, our guide on GSTR-1 and its structure explains it in detail.

With the upcoming Invoice Management System (IMS), quantity accuracy will matter even more. A wrong UQC today can easily turn into return mismatches tomorrow.

Why Taxpayers Face UQC Errors

This is where confusion usually begins.

Businesses often use different internal terms such as:

• m

• mtr

• metre

• meters

• metres

The GST portal accepts only one approved format.

For metre, that format is:

MTR – METERS

Anything else leads to upload failure.

The portal does not auto-correct. It simply rejects.

If you use the GSTR-1 offline tool, always select the quantity code from the dropdown list. Manual typing often causes errors.

Even if your internal system uses a different unit, GST reporting must follow the prescribed UQC only.

List of Unique Quantity Codes or UQC Codes

GST does not publish a separate list for quantity units.

Instead, the system continues to follow Customs Quantity Codes, which are accepted across GST filings.

Only the first three letters are used as the code.

Below is the commonly used UQC code list in GST format.

If your product does not fit any category, use OTH – Others.

Practical Examples of UQC Usage

UQC should match how the goods are normally measured and sold.

• Selling steel rods by weight: Use KGS since the sale is based on kilograms.

• Selling fabric by length: Use MTR as textiles are measured in meters.

• Selling medicines in strips: Use PCS or TBS, depending on how the product is packed and billed.

• Selling machinery by count: Use NOS when items are sold as individual units.

Choosing the correct code keeps invoice data aligned across e-invoices, e-way bills, and GST returns, and avoids validation errors during filing.

Why UQC accuracy matters

Incorrect quantity codes can lead to:

• Failed JSON uploads

• GSTR-1 validation errors

• E-invoice rejections

• Mismatch with buyer’s ITC data

• Delays under IMS reconciliation

GST systems now cross-check invoice data line by line. Quantity is no longer ignored.

Conclusion

UQC may look like a technical detail, but GST compliance lives in details. The right code keeps your invoices clean. The wrong one stops your filing cold.

As GST systems move toward real-time matching through IMS, accurate quantity reporting will become non-negotiable. If managing returns, invoices, and reconciliations is starting to feel heavier than it should, our team at LegalWiz help simplify GST return filing with structured tools, expert support, and fewer late-night error fixes. Sometimes compliance just needs the right backup.