UPC barcodes are normally used to encode two pieces of information: the ID assigned to the company responsible for creating or selling a product and the code that company assigns to that particular product. Only in very rare cases, by analyzing a 12-digit barcode, it is possible to extrapolate additional information. By learning to read barcodes, you can impress your friends by managing to derive the encoded number from the series of bars and blanks that compose them. Train by covering the number encoded in the barcode displayed at the bottom trying to derive it through the simple interpretation of the series of bars and empty spaces.
Steps
Method 1 of 2: Interpret the 12 Numbers Printed on a Barcode
Step 1. Search online
The UPC system (now known as UCC-12) simply encodes the manufacturer's identifier and the code assigned to a particular product. Except for a few special cases described in these steps, this is the only information you can glean from your interpretation of a barcode. Search online using one of the free services, such as GTIN, the official US site for assigning barcodes, or upcdatabase.org, a site based on a database created by the users themselves. Enter the entire number contained in the barcode in the text field that you find on the web page of the two search engines indicated.
- In the following steps we will describe some exceptions where you can find additional information within a barcode.
- GTIN stands for Global Trade Item Number, a system for creating barcodes that refers to UPC coding. 12-digit UPC barcodes are also referred to as GTIN-12, UPC-A, or UPC-E.
Step 2. Understand the basics of barcodes
Even though barcodes don't contain information that is readily understood by a human eye, you can still learn what their function is. The group consisting of the first 6-10 digits of a UCC-12 barcode identifies the company that produces or sells the product in question (in case the two companies are different they could choose to add both barcodes). This identifier is assigned and sold upon request by a non-profit organization, GS1. The remaining figures, except the last one, are used by the company itself to identify its products.
- For example, assume that a company is identified by the number "123456". The company in question will be able to print its own barcodes which must all begin with the number "123456", followed by the code that identifies each individual product. Compare the barcodes of two objects produced by the same company to find what the company identifier is.
- The purpose of the last digit in a barcode will be explained later in this section.
Step 3. Learn to interpret a barcode where the first digit is a "3"
Medicines, pharmaceuticals and, occasionally, cosmetics have barcodes starting with the number "3". The next 10 digits normally correspond to the "National Drug Code" assigned to the specific product. The process of transforming an NDC identifier into a barcode can generate an ambiguous result, so you won't always be able to interpret it by comparing it to the available NDC lists. In this case, try to search online using a specific search engine.
- This type of 12-digit identifier is sometimes referred to as UPN, ie "Universal Product Number".
- Although drug identification codes consist of 10 digits, they can still include dashes or spaces within them that do not appear in the resulting barcode. For example, the following identifiers 12345-678-90 and 1234-567-890 represent two different codes, but only one can use the same sequence of numbers within the barcode.
Step 4. Understand the meaning of the barcodes starting with the number "2"
This type of barcodes are used for goods sold by weight. In this case the first 6 digits of the code, including the "2", identify the manufacturing company, while the next 5 are used by the local store or warehouse to describe the weight of the product or the price for a given quantity. Assuming you have different products from the same company, but with different weights, you may be able to trace the portion of the barcode that identifies each weight. Unfortunately, the coding system is at the discretion of the store or warehouse, so you won't have a universal code to interpret.
To locate the manufacturer of a particular product, enter the entire barcode in the "GTIN" field of the following search engine. By doing so, you will also be able to trace the portion of the barcode that identifies the company (normally, but not always, corresponding to the first 6 digits). The remaining numbers (except the last digit) should be the identifier used to encode the weight or price
Step 5. Find out the meaning of the final digit
The last digit of a barcode is called a "check digit" and is calculated automatically by entering the other digits of the code into a suitable mathematical formula. The purpose of this calculation is to identify any printing errors. While there are some fake UPC barcodes in circulation, usually created by companies that don't know the correct procedure for obtaining one, being able to include the correct check digit is very simple; this method is therefore not useful for detecting fake barcodes (if you want to find out the authenticity of a barcode, do an online search in the official database). If you love mathematics or are simply curious to check if a barcode is correct, you can use the appropriate automatic tool or use the following mathematical formula:
- Add up all the odd digits of the barcode in question (first, third, fifth, seventh, ninth and eleventh);
- Multiply the result by 3;
- To the result obtained, add the sum of all the even digits of the barcode in question (second, fourth, sixth, eighth, tenth and twelfth), without including the check digit;
- From the result obtained, discard all digits except the last one (this process is called "Modulo 10" and consists of dividing a certain number by 10 and using the remainder of the division as the result).
- If that number is 0, it will be the check digit.
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Subtract the result from the number 10 to find the "check digit". For example, if the result of the previous calculation was 8, the calculation to be performed will be the following 10-8 =
Step 2.. The number obtained must correspond to the twelfth digit of the barcode.
Method 2 of 2: Read a Number-Free UPC Barcode
Step 1. Learn the following method
Even though the barcodes are designed to be read by special electronic readers and interpreted by computers, with a little practice it is still possible to decode the UPC barcodes into their 12-digit number. However, this is not a very useful process as the number encoded in a barcode is often printed at the bottom of the barcode. In any case, learning this trick can help you entertain friends and colleagues in your free time.
Barcodes that do not comply with the UPC coding system cannot be read using this method. The barcodes found on most products sold in the United States and Canada comply with the UPC system. But beware of those 6-digit UPC codes that use a different and much more complex coding system
Step 2. Find the three longest bars
A barcode should appear divided into three sections, thanks to three bars that extend in length. Look at the bottom of the barcode to find the three bars that are longer than the others. There should be two such bars at the beginning of the code, two in the middle and two at the end. These elements are inserted to facilitate the reading of the code by electronic readers, but they also play a key role in this method. The two bars placed at the beginning of the code, to the left of the central ones, must be interpreted in a slightly different way than those placed on the right. This concept will be explained in detail later.
Step 3. Identify the four bar templates
Each bar that makes up the code (black or white) can be traced with one of the four available thicknesses. Starting from the thinnest to the thickest, we will identify these bars with the numbers 1, 2, 3 and 4. If necessary, use a magnifying glass to identify the four thicknesses and consequently the four models of bars that make up the code. Finding the difference in thickness between two similar lines is the hardest part of the barcode decoding process.
Remember that the numbers 1, 2, 3 and 4 are used for convenience and only serve to identify the four models of bars present in a code, so they are not to be confused with the numbers they represent in reality
Step 4. Note the thickness of the bars on the left
Start analyzing the barcode from the left, examining the section between the two longest center bars and those on the far left. Start by examining the white bar on the left of the section in question and measure its thickness, then continue for each of the following bars. Each of the 12 numbers that are encoded in the barcode is expressed as a set of 4 bars. Take note of the thickness of each line, then divide the set of numbers obtained into groups of 4. When you reach the two longest central bars that divide the barcode into two halves, you will have identified 6 groups of numbers each consisting of 4 digits.
- For example, if the first white bar after the two longest lines delimiting the barcode on the left side has the thinnest thickness, identify it with the number 1.
- Going to the right, if the next black bar has the widest thickness, identify it with the number 4.
- When you have completed decoding the first group of 4 bars (both white and black), leave a separating white space before proceeding to examine the next group. For example, assuming you have the following set of numbers "1422", move to a new line to examine the next set of lines.
Step 5. Follow the same procedure to examine and decode the thickness of the bars in the right half of the code
Note that in this case the sequence will start with a black line. Obviously, do not take into account the two longer center lines used only as delimiters. Start by looking at the first black line on the right which has a normal length and use the same technique explained in the previous step. This time each group of 4 lines will consist of the following "black-white-black-white" pattern. Once you have obtained the next 6 groups of numbers consisting of 4 digits each, you will have completed your decoding. Again, do not include the two longest trailing lines on the far right of the barcode.
Step 6. Decode the numbers assigned to the individual bars
After obtaining the set of numbers, each of which identifies the thickness of each single line that makes up the barcode, you will only have to find out how to transform them into the 12 real numbers encoded within the code itself. To do this, use the following scheme:
- 3211 = 0
- 2221 = 1
- 2122 = 2
- 1411 = 3
- 1132 = 4
- 1231 = 5
- 1114 = 6
- 1312 = 7
- 1213 = 8
- 3112 = 9
Step 7. Check the result
If the numbers encoded in the barcode appear directly at the bottom of the barcode, you can perform a quick visual check to find out whether or not you have made a mistake. Alternatively, you can perform an online search using the GTIN website database and entering the 12 numbers derived from your analysis in the "GTIN" text field. This way you should be able to locate any product distributed or sold by a company that has been assigned a valid barcode. Sometimes, however, it may happen that companies print internal barcodes that have not been entered in the international system: in this case your search will not produce any results. However, in most cases, querying the GTIN site database will result in the exact product in front of you - assuming you have correctly interpreted its barcode.
Advice
- Outside the United States and Canada, the most popular barcode creation system is the 13-digit EAN. The EAN system requires the use of an additional digit as part of the country code. To adapt a UPC barcode to the EAN system, a "0" is simply added to the left of the number. This "0" is used to identify the area of the United States and Canada - however, note that the country that sells a particular product is encoded in the barcode, not the country that created it.
- By typing the barcode of your interest directly on Google, you will be redirected to the specific search engine for this type of data: www.upcdatabase.com.
