Alphanumericals facts for kids

A black-headed gull ringed with an alphanumeric plastic ring that makes it easier to read from a distance.

Alphanumeric characters are a special mix of letters and numbers. Think of them as a combination of the letters from the Latin alphabet (like A, B, C) and the numbers we use every day, called Arabic numerals (like 0, 1, 2).

When you see an alphanumeric code, it's usually a unique identifier made up of these letters and numbers. For example, your password might be an alphanumeric code!

Sometimes, the word "alphanumeric" can also include other symbols, like punctuation marks or math symbols. It really depends on who is using the term and for what purpose.

Computers often use alphanumeric characters too. In some computer systems, there are 36 alphanumeric characters (A-Z and 0-9, where uppercase and lowercase letters are treated the same). In other systems, there are 62 characters (A-Z, a-z, and 0-9, where uppercase and lowercase letters are treated differently).

Why Alphanumeric Codes Are Important

Alphanumeric codes are super useful because they let us create many different combinations. This is great for making unique identifiers for almost anything!

Making Codes Easy to Read for Humans

Sometimes, when we use a mix of letters and numbers, it can get a bit confusing. Some letters look a lot like numbers, which can lead to mistakes. For example, the letter I can look like the number 1, and the letter O can look like the number 0. The letter Q can also look like 0.

To avoid these mix-ups, people often create special sets of alphanumeric characters for different uses. These sets leave out the confusing letters.

Alphanumeric Codes in Everyday Life

You might not even realize it, but you see these special alphanumeric codes all the time!

• Airplane Seats: Have you ever looked at an airplane seat map? Seats are usually labeled with a row number followed by a column letter. On big planes, there might be 10 seats across. To make sure no one confuses a seat letter with a row number, the letter I is often skipped. So, you might see seats labeled A, B, C, D, E, F, G, H, J, K, but no I!

• Vehicle Identification Numbers (VINs): Every car has a unique VIN, which is a long alphanumeric code. Car makers avoid using the letters I, O, and Q in VINs. This helps prevent mistakes when people read or write down these important numbers.

• Electrical Connectors: Even tiny parts like pins on electrical connectors use alphanumeric labels. To make it easier to read these small labels and reduce eye strain, certain letters are left out. For example, the letters I, O, Q, S, and Z were removed because they look too much like the numbers 1, 0, 5, 3, and 2. This special set of characters is sometimes called the DEC Alphabet.

• Handwritten Codes: When people write alphanumeric codes by hand, it can be even harder to tell some characters apart. Besides I and O, the letter V is sometimes avoided because it can look like U when written in cursive. Also, Z can look like 2.

By carefully choosing which letters and numbers to use, we can make sure that important codes are clear and easy for everyone to understand, whether they are typed or handwritten.

See also

In Spanish: Alfanumérico para niños

• Alphanumeric brand names
• Alphanumeric shellcode
• Alphanumeric keyboard
• Binary-to-text encoding
• Mathematical Alphanumeric Symbols