UPC-A
Universal Product Code (12-digit)
What is UPC-A?
UPC-A (Universal Product Code, version A) is the standard barcode symbology used on retail products in the United States and Canada. It encodes a 12-digit GTIN (specifically a GTIN-12) as a pattern of vertical bars and spaces readable by any standard barcode scanner.
Introduced in 1974, UPC-A was the first barcode symbology widely adopted for retail checkout. A UPC-A is technically a subset of EAN-13 : prepending a 0 to any 12-digit UPC-A number produces a valid 13-digit EAN-13 number. This means every UPC-A barcode can be read by EAN-13 scanners worldwide, and the underlying identifier is the same GTIN used in RFID SGTIN encoding.
Used for: Retail point-of-sale in the US and Canada, inventory management, supply chain logistics, and as the source identifier for SGTIN EPC encoding on RFID tags.
Structure
A UPC-A number is 12 digits long. The first digit is the Number System Digit, which categorises the type of product. The boundary between the Company Prefix and Item Reference is variable, assigned by GS1 US based on how many product numbers a company needs.
| Field | Digits | Description |
|---|---|---|
| Number System Digit | 1 | Indicates the category of the product. 0 is the most common value for standard retail merchandise. 2 indicates variable-weight items (such as meat or produce priced by weight). 3 is used for pharmaceuticals (National Drug Code). 5 is for coupons. |
| Company Prefix | 5 - 9 | The GS1 Company Prefix assigned to the brand owner by GS1 US. Together with the Number System Digit, this identifies who owns the number. Longer prefixes leave fewer digits for item references. |
| Item Reference | 1 - 5 | Assigned by the brand owner to identify a specific product (SKU) within their allocated number range. |
| Check Digit | 1 | The final digit, calculated using the GS1 mod-10 algorithm. Catches scanning and transcription errors. |
Example: UPC-A
036000291452 In this example, 0 marks a standard retail item, 36000 is the GS1 Company Prefix (assigned to a company by GS1 US), 29145 is the item reference chosen by the brand owner, and 2 is the mod-10 check digit.
How UPC-A relates to EPC / RFID
A UPC-A encodes a GTIN-12. To convert it for RFID encoding in an SGTIN EPC, the GTIN-12 is first expanded to a GTIN-14 by prepending two zeros (one for the EAN-13 leading zero and one for the indicator digit):
- UPC-A to EAN-13: Prepend a
0to the 12-digit UPC-A number. This produces the EAN-13 equivalent:036000291452becomes0036000291452. - Pad to GTIN-14: Prepend an indicator digit (typically
0for the base trade item) to get 14 digits:00036000291452. - Drop the check digit: The check digit is removed because it can always be recalculated. This leaves 13 digits.
- Split into fields: The indicator digit becomes part of the item reference field in the SGTIN. The GS1 Company Prefix goes into the company prefix field.
- Add a serial number: A unique serial number is appended. In SGTIN-96 the serial is numeric only (up to 38 bits); in SGTIN-198 it can be alphanumeric (up to 140 bits).
Example mapping
| Layer | Value |
|---|---|
| UPC-A barcode | 036000291452 |
| EAN-13 equivalent | 0036000291452 |
| GTIN-14 (zero-padded) | 00036000291452 |
| Indicator | 0(first digit of GTIN-14) |
| Company Prefix | 0036000 |
| Item Reference (in SGTIN) | 029145(indicator 0 + reference 29145) |
| Serial Number | 4200(assigned per individual item) |
| Pure Identity URI | urn:epc:id:sgtin:0036000.029145.4200 |
Because a UPC-A is just a GTIN-12, and all GTIN formats normalise to GTIN-14 before EPC encoding, a product identified by UPC-A in the store and by SGTIN on an RFID tag carries the same underlying identifier. The RFID tag simply adds a serial number for individual-item tracking.
Where UPC-A is used
- US and Canadian retail: Nearly every product sold in a supermarket, pharmacy, or mass-merchandise store in North America carries a UPC-A barcode.
- Global compatibility: Because UPC-A is a subset of EAN-13 (prefix with a leading zero), UPC-A barcodes can be scanned by EAN-13 readers anywhere in the world.
- Warehousing and distribution: Used on individual units and inner packs. Cases and pallets typically use GTIN-14 barcodes (ITF-14 or GS1-128) that incorporate the same company prefix.
- Apparel and fashion: Clothing in the US uses UPC-A for the base product and increasingly RAIN RFID (SGTIN) tags for item-level inventory visibility.
- Coupons: UPC-A barcodes with Number System Digit
5encode manufacturer coupon information, following the GS1 US coupon format.
Related EPC schemes
Source
GS1 EAN/UPC Barcode Standards and the GS1 General Specifications. The GTIN-to-SGTIN encoding procedure is defined in the GS1 EPC Tag Data Standard.