ASCII to Octal Conversion Table: Complete - Tech With Tech

ASCII to Octal Conversion Table: Complete

The complete ASCII to octal conversion table.

This ASCII to octal table contains all 256 ASCII characters and their octal counterparts.

So if you want to get the complete ASCII to octal conversion table, then this article is for you.

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ASCII to Octal Conversion Table: Complete (PDF File)

What Is ASCII in a Nutshell?

Have you ever stopped to wonder how your computer works?

You may know that computers use binary (combinations of the numbers zero and one) to store information, but how does that translate into the comprehensive text you read on your screen?

The answer lies with ASCII.

ASCII Explained

ASCII stands for the American Standard Code for Information Interchange. Essentially, it is the computer’s own language.

Computers have a seven-digit code to represent each letter, number, and punctuation. This code is binary, so it only uses a combination of zeros and ones. 

For example, the bits (binary digits) for a capital A are 01000001, while the bits for a lowercase A are 01100001. 

If you counted how many digits there are, you might be confused about why there are eight digits instead of seven.

Well, each byte in the standard ASCII starts with zero, so the following seven digits are those that differentiate the characters.

ASCII has codes for 255 characters.

Instead of remembering the byte for each letter, symbol, and number, the founders organized them numerically and assigned them a decimal value.

For example, capital A (as mentioned above) is number 65, while the lowercase A is 97. 

ASCII Sections

To further organize these codes, the founders separated the characters into two sections, which later became three as people developed codes for more specialized characters. 

The first ASCII section is a control group that contains unprintable characters.

There are a total of 32 characters in this subgroup, labeled from 0 to 31.

These unprintable numbers are only to control different external devices, like a keyboard or a printer. 

White printer with black computer.

In the next section, you’ll find the printable characters that occupy spaces 32 to 127.

Any character you see on the keyboard will be in this group, from the % symbol to the letters and numbers.

Even the spacebar and the delete key have their own codes (numbers 32 and 127, respectively). 

The final section, ranging from character code 128 to 255, was a more recent addition.

Every code has eight bits, each starting with one (as opposed to zero as in the previous two sections).

The characters in this section vary depending on the particular operating system language you are using. Many foreign characters (like Á and Ö) fall into this category.

History of ASCII

Sixty years ago, a conversation about creating a unified coding system for all types of characters began.

The first meeting of the American Standard’s Association’s subcommittee X3.2 occurred in October 1960, and the members started with a teleprinter code from the Bell company. 

From there, they published the first version in 1963, which only had numbers and capital letters. In 1967, they added the first section of control characters and lowercase letters. 

Fourteen years later, they implemented the extension group. This third section includes characters from 128 to 255. 

The majority of computing systems still use ASCII, but new variations are becoming popular with specific systems.

Using the ASCII

Whether you’ve realized it or not, you already use ASCII! Just using a computer system utilizes the ASCII. 

Nevertheless, it’s helpful to learn and understand ASCII—even if you aren’t interested in the technical details – so you can quickly get a foreign language letter whenever you need it. 

For example, with Windows, you can press the ALT key and the given code to get any particular character.

Instead of copying and pasting those accented letters or unique currency signs, you can use this quick method not to break the flow of your typing. 

Variations of ASCII

Since the ASCII contains mainly American characters, several variations with non-English letters developed around the world.

The International Organization for Standardization (ISO) created the third section of the ASCII, including eight-bit codes.

The extension, called the ISO 8859, has numerous language variations.

  • Western European languages: Latin-1
  • Eastern European and non-Cyrillic central languages: Latin-2
  • Esperanto and southern European languages: Latin-3
  • Northern European languages: Originally Latin-4, now called Latin-10 or Latin-6
  • Turkish: Latin-5
  • Cyrillic: 8859-5
  • Arabic: 8859-6
  • Greek: 8859-7
  • Hebrew: 8859-8

The numerous names for the code for northern European languages show that the information interchange code is continually changing as people develop more efficient systems.

A fantastic example of these continual changes is the creation of Unicode.

The Universal Coded Character Set aims to provide a completely comprehensive code set for all characters.

There are currently 143,859 characters, including historical scripts and emojis. 

Thanks to its goal of including thousands of characters, it has become a popular choice for computer software.

Learn every little tiny bit about ASCII in this in depth article about ASCII: What Is ASCII & What Is ASCII Used For?

What Is the Octal Numeral System in a Nutshell?

Numeral systems are used to describe quantities and represent specific information.

Without a numeral system, for example, you wouldn’t be able to declare the word “number” contains six letters. 

As a kid, you’re taught to count with your fingers.

First, to five, using one hand.

Then, to ten using the other.

What if I told you there was another way?

Try this, instead of using each finger to illustrate your count, use the spaces in between them. 

By doing so, you’ve just used the octal numeral system.

Otherwise known as oct, the octal numeral system is the base-eight system that uses the digits zero through seven.

The octal system is similar to binary (base 2) and hexadecimal (base 16). 


The integer symbols for the octal numeral system are 0, 1, 2, 3, 4, 5, 6, and 7.

The smallest two-digit number in oct is used for the decimal number 8 and is expressed as (10)8. 

Multi-digit numbers in this system need to be written with a base of 8. For example, (352)8.

If not, the number will be assumed to be decimal, leading to significant discrepancies in the number system base. 

How Octal Numeral Systems Are Used

Languages associated with Native American tribes from California and Mexico use octal systems.

For example, the Yuki and Pamean languages use octal systems by counting with the spaces between fingers, as mentioned above. 

European versions are present in history as well.

In the 18th century, Swedish royalty implemented an eight integer system.

Octal based system proposals occurred in Britain and France as well.  

However, Octo’s most prevalent usage came in the form of computers, and more specifically, minicomputers.

Norsk Data ND-500 computer.

At one time, octal was the ideal abbreviation of binary numbers for 6-bit, 12-bit, 24-bit, and 36-bit words because it uses three-bit binary coding. 

AT&T developed a popular computer operating system in the seventies called Unix.

It was written in octal because it grouped three bits at a time to perform its read, write, and execute functionality.

An octal number such as 0123, in this case, would communicate by sending 001 to the first controller, 010 to the second, and 011 to the third. 

An individual digit in an octal numeral is equivalent to three digits in a binary numeral.

Grouping binary digits is done from right to left.

The initial three binary digits from the right group into the last part of the octal numeral.

The subsequent three digits form the next and last parts of the numeral.

For example:

  • octal numeral 1 = 001 binary numeral
  • octal numeral 2 = 010 binary numeral
  • octal numeral 3 = 011 binary numeral
  • octal numeral 10 = 001 000 binary numeral

Octal representation is shorter in characters and more concise than binary.

Octal to Decimal

The decimal system is the base-10 numeral system, which most people are familiar with.

As mentioned earlier, counting on your fingers to ten is an example of using the decimal system.

The decimal system uses the integers zero through nine, with the lowest double-digit number being 10. 

A decimal number is determined by the sum of the digits multiplied to the tenth power (10^n). 

For example: 132 in base 10 = 1×10^2+3×10^1+2×10^0 = 130+30+2

Octal numbers can be depicted the same way, except digits are calculated using the eighth power (8^n).

When converting an octal number to its equivalent in the decimal system, you expand the number in base eight with its positional weight. The result will be the decimal number.

For example: 317 in base 8 = 3×8^2+1×8^1+7×8^0 = 207

The following table demonstrates the difference between octal and decimal when counting zero to hundred:

Decimal to octal one 1 to 100 table.

Advantages for Using Octal Numeral System

There are three primary advantages of using the octal numeral system. They are:

  • It is expressed in one-third of the length of the binary system
  • The conversion process from binary to octal and octal to binary is simple
  • It is easier to process input and output in oct

Disadvantages for Using Octal Numeral System

Computers don’t recognize the octal number system by default like they do binary.

So, to use oct in a computer, there needs to be a requirement for additional circuitry known as an octal to binary converter.  

Using the octal numeral system provides the most benefit in 3-bit word processing systems. Otherwise, its usage is fairly arbitrary. 

Complete ASCII to Octal Table

Complete ASCII to octal table.

Find the complete ASCII master table in this in depth article about ASCII.

Complete ASCII to Octal Table as PDF

More ASCII Tables

If you’re looking for any other ASCII conversion table than the complete ASCII to octal table, then you’ll find it here.

All tables come as a PDF version as well: