This question comes up all the time so I thought I would write another post approaching the topic. What is the source of those numbers/barcodes you see on products? Is there someone who issues them?
There are many different kinds of barcode and numbering system. I could come up with my own series of numbers designating, say, what I plan to cook for lunch each day of the week – 000001 could be macaroni cheese, 000002 could be chicken vindaloo and so on. I could put these numbers in a barcode generator and then read the resulting barcodes with a barcode reader when I wanted to know what was for lunch. Any individual or company could (and they most certainly do) come up with a numbering system to track their own inventory, goods going in and out, etc. etc. These numbers can be encoded in any one of many barcode systems that exist out there and can be read by a reading device – and they can, and very often are entirely internal.
Think of supermarkets – when you buy a product by weight they will stick a label with a barcode on it which then gets read at the checkout and the system knows the price because at the moment of weighing and labelling, the system recorded the price, generated an ad hoc number which it stored in its system against that price (which the checkout till will later retrieve) and generates a barcode using one of the common barcode systems out there. But although this bar code could probably be read by any barcode reader, it wouldn’t mean anything to that system – it would just be a number like 2342343456345 – or it might equate to a completely different product in that company’s system. The number would only mean the correct thing to the system in which it was stored.
Bar codes as such are independent of the kind of numbering system used – the number is one thing, how you are going to encode it in a barcode is another issue. You don’t HAVE to encode it in a barcode at all, you could scribble the number down in pencil and make the person trying to track the product read and type the number into their system manually! The barcode is for ease and speed of machine reading.
But I expect what people are primarily thinking of when they ask this is the UPC and EAN codes found on almost all products sold in the US and Europe/rest of the world respectively. These are 12- and 13-digit codes that are totally unique and can only be used once to identify a single product (or only SHOULD be used that way, if you want to avoid confusion). These codes are broadly known as GTIN (Global Trade Item Number) codes and are issued by a central organisation (GS1) to companies/manufacturers, who buy up whole ranges of them, usually prefixed by a number that designates the company so their products can be identified as belonging to them.
But here’s the catch, the GS1 does NOT know what product belongs to what UPC/EAN/barcode, they simply issue unique numbers. It is down to the owner of the unique codes to then issue them to particular products, maintain their own records of which product belongs to which code, to mark the product with the code/barcode and to use it when distributing their product further.
This is why there is no “central” database of product codes and why people like me make 3rd-party sites to try to track them, and I hope this also answers the question of who originates the codes. GS1 issue them – but the owner of the code allots it to a particular code.