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UPC Check Digit Calculator

Calculate or validate a UPC-A check digit and see its 14-digit GTIN representation.

Example values are filled in. Change them to match your job; results update automatically.

How to use this tool ↓

Your inputs

Replace the example values with your own.

Leading zeros are preserved. UPC-A uses numeric digits only.

Calculated result

Identifier typeUPC-A / GTIN-12
Check digit2
Complete number036000291452
14-digit GTIN representation00036000291452
5×3 + 4×1 + 1×3 + 9×1 + 2×3 + 0×1 + 0×3 + 0×1 + 6×3 + 3×1 + 0×3 = 58 Check digit = (10 − (58 mod 10)) mod 10 = 2

The two leading zeros are filler digits for systems that require a uniform 14-digit GTIN field; they do not create a different trade item identifier.

This calculator checks modulo-10 arithmetic only. It does not verify allocation, ownership, licensing, or GS1 certification.

How to use this calculator

  1. Choose calculation for an 11-digit body, or validation for a complete 12-digit UPC-A.
  2. Enter digits only, including any leading zeros.
  3. Read the completed UPC-A. Use the zero-padded GTIN representation only where your receiving system expects 14 digits.

This tool handles UPC-A, not compressed UPC-E numbers.

Formula and method

UPC-A uses the GS1 modulo-10 method. From the rightmost body digit, alternating weights 3 and 1 are applied before the final digit completes a multiple of ten.

Read the methodology and source notes →

Worked example

UPC-A body 03600029145 has check digit 2, producing the complete number 036000291452.

How to interpret the result

Use validation to catch many typing errors before creating or checking a UPC-A symbol. Preserve leading zeros.

UPC-A and a 14-digit GTIN field

UPC-A carries a 12-digit GTIN-12. Systems that require a uniform 14-digit GTIN field represent the same identifier by adding two leading filler zeros; for example, 036000291452 becomes 00036000291452.

Removing leading zeros from an arbitrary GTIN-14 is not a general conversion to UPC-A. The reverse is only unambiguous when the 14-digit value is a zero-padded GTIN-12 representation.

Limitations

Checksum validity does not establish that a UPC was licensed, assigned to the stated product or encoded with compliant dimensions.

Primary references

Related tools

Related guides

Usage instructions updated October 19, 2026.
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