The "UPC-A bar code" is by far the most common and well-known symbology, at least in the United States. An UPC-A bar code is the bar code you will find on virtually every consumer good on the shelves of your local supermarket, as well as books, magazines, and newspapers. It is commonly called simply a "UPC bar code" or "UPC Symbol." This isn't entirely accurate since there are a number of other UPC formats (UPC-E, UPC 2-Digit Supplement, UPC 5-Digit Supplement).

Sample of a UPC-A Barcode
The value to encode by UPC-A has the following structure:
-
1 digit for Number System (0: regular UPC codes, 1: reserved, 2: random weight
items marked at the store, 3: National Drug Code and National Health Related
Items code, 4: no format restrictions, for in-store use on non-food items, 5:
for use on coupons, 6: reserved, 7: regular UPC codes, 8: reserved, 9:
reserved)
-
5 digits for Manufacturer (Company) Code or prefix. This number is assigned by
the Uniform Code Council (UCC)
-
5 digits for Product Code which is assigned by the manufacturer
-
1 digit for checksum
Add-On or Supplement code
The Add-On Symbols were designed to encode information
supplementary to that in the main bar code symbol on periodicals and paperback
books. The Add-On can be composed of 2 or 5 digits only.

Sample of an UPC-A Two-Digit Add-On Barcode

Sample of an UPC-A Five-Digit Add-On Barcode
UPC-A Barcode for .NET, ASP.NET supports:
- 0, 1, 2, 3, 4, 5, 6, 7, 8, 9
- Add Reference BarcodeLib.Barcode.dll to your .NET project (ASP.NET website, Forms, any .NET project)
In your .NET class.
BarcodeLib.Barcode.Linear.Linear barcode = BarcodeLib.Barcode.Linear.Linear();
barcode.Data = "your barcode data";
// other barcode settings.
// save barcode image into your system
barcode.drawBarcode("c:/barcode.gif");
* Please set properties
UOB and
Resolution, before you set any image size related properties like barWidth, margin.