I would imagine that the vast majority of people who look at barcode numbers and images have no idea what the numbers stand for and how they are derived. Well this blog should shed some light on that issue, and will give you a simple method by which to test your own codes.
The above image is a simple test-barcode number that we will use as an example for this blog. First thing to notice is that it is an EAN-13 code, rather than a UPC code. The only difference between the two is that an EAN code is 13 digits long, while a UPC code is only 12 digits in length. The reason why we have two variations of retail codes is because when barcode technology was first develop in the States back in the early 70’s, they decided to use only 12 digit codes (UPC). However, when the barcode system started to take off around the world GS1 (known as the UCC back then) decided to introduce an extra digit to allow for the increasing numbers of codes required. When they made this move, they instigated a country prefix for each country in which barcodes would be registered. Some common country prefixes that you will come across are the following:
United states: 000-139
South Africa: 600-601
United Kingdom: 500-509
Based on these examples it is clear that our test-barcode would have originated from the US. It is important to remember that this number only tells you where the barcode was first registered, not where the retail product was manufactured. For this reason, many Chinese manufacturers will purchase US barcodes for their products so that US consumers will not think that they are buying Chinese products, sneaky sneaky 🙂
So that takes care of the first 3 digits, but what about the remaining 10 barcode numbers. Well, here is the answer. The next 5-7 numbers represent the manufacturers code. So if BP were to order a barcode directly from GS1 south africa, they would be assigned their own unique manufacturers code. From then on, whenever BP brought out a new product, their barcodes would have their company code as part of the list of numbers. After the manufacturers code comes the individual product code (3-5 digits) which is the way that each product can be differentiated from the rest. Most companies don’t actually register their individual products on the GS1-system, but this gives them the option to do it if they so desire.
The last digit in every barcode number is the famous ‘check digit’. This is used to make sure that all the rest of digits were read correctly by the scanner. The way that the check digit works is by way of a mathematical formula which is applied to the preceding digits. If the numbers are scanned correctly, the formula will spit out the check digit and the scanner will know that it read the barcode exactly right.
The formula is as follows (Mathematics Ep, 2012):
3 X (1st + 3rd + 5th + 7th digits) + (2nd + 4th + 6th + check digit) = Y
If the answer “Y” is divisible by 10, then the barcode scanner know that the number has been read correctly. It is as simple as that. Here is a diagram that clearly shows the number allocations on a standard GS1 EAN code.
So I hope that this blog post helps a few people to understand the mystery behind barcode numbers, they are actually not very complicated and we hope that you will spread the word about it. Best Wishes,