ASCII and UNICODE are the two most extensively used character encoding schemes in computer systems. The most basic difference between ASCII and UNICODE is that ASCII is used to represent text in form of symbols, numbers, and character, whereas UNICODE is used to exchange, process, and store text data in any language.

What is ASCII?

ASCII stands for American Standard Code for Information Interchange. It is a standard developed for character encoding in electronic communication. ASCII was first published in 1963. In computers and other electronic systems, it is used for representing text as symbols, characters, and numbers.

In ASCII, each letter is assigned a particular value between 0 and 127. Thus, ASCII can be used to represent 128 characters. Most computer systems use ASCII encoding scheme that makes the interchange of data among different devices simple.

The following table shows some of the symbols and their ASCII values.

Name Symbol ASCII Value Binary Code
Null char NUL 0 00000000
Start of Heading SOH 1 00000001
Substitute SUB 26 00011010
Escape ESC 27 00011011
File Separator FS 28 00011100
Group Separator GS 29 00011101
Record Separator RS 30 00011110
Unit Separator US 31 00011111
Space 32 00100000
Exclamation mark ! 33 00100001
Double quotes " 34 00100010
Number # 35 00100011
Dollar $ 36 00100100
Procenttecken % 37 00100101
Ampersand & 38 00100110
Single quote ' 39 00100111
Left parenthesis ( 40 00101000
Right parenthesis ) 41 00101001
Asterisk * 42 00101010
Plus + 43 00101011
Comma , 44 00101100
Hyphen - 45 00101101
Period or Dot or Full stop . 46 00101110
Slash or divide / 47 00101111
Zero 0 48 00110000
One 1 49 00110001
Two 2 50 00110010
Eight 8 56 00111000
Nine 9 57 00111001
Colon : 58 00111010
Semicolon ; 59 00111011
Less than < 60 00111100
Equals = 61 00111101
Greater than > 62 00111110
Question mark ? 63 00111111
At symbol @ 64 01000000
Uppercase A A 65 01000001
Uppercase B B 66 01000010
Uppercase C C 67 01000011
Uppercase D D 68 01000100
Uppercase X X 88 01011000
Uppercase Y Y 89 01011001
Uppercase Z Z 90 01011010
Opening square bracket [ 91 01011011
Backslash \ 92 01011100
Closing square bracket ] 93 01011101
Caret - circumflex ^ 94 01011110
Underscore _ 95 01011111
Grave accent ` 96 01100000
Lowercase a a 97 01100001
Lowercase b b 98 01100010
Lowercase c c 99 01100011
Lowercase d d 100 01100100
Lowercase e e 101 01100101
Lowercase v v 118 01110110
Lowercase w w 119 01110111
Lowercase x x 120 01111000
Lowercase y y 121 01111001
Lowercase z z 122 01111010
Opening curly brace { 123 01111011
Vertical bar (Pipe) | 124 01111100
Closing curly brace } 125 01111101
Equivalency sign (tilde) ~ 126 01111110
Delete 127 01111111

What is UNICODE?

UNICODE stands for Universal Character Set. UNICODE is an encoding scheme whose standards are maintained by UNICODE Consortium. The greatest advantage of UNICODE is that we can uniquely define every character in every language by giving a different number.

UNICODE represents a wide range of characters, formulae, texts, mathematical symbols, emojis, greek letters, etc. from different languages. Therefore, UNICODE is the one of the most popular encoding scheme to encode many of the globally used characters.

UNICODE encoding schemes are classified into several types depending on the number of bits used. These UNICODE encoding schemes are UTF-7 (7-bit encoding scheme), UTF-8 (8-bit encoding scheme), UTF-16 (16-bit encoding scheme), and UTF-32 (32-bit encoding scheme). Here, UTF stands for UNICODE Transformation Format, which is a type of UNICODE encoding scheme.

The main objective of the use of UNICODE is localization and internationalization of computer applications and software. UNICODE is also used for programming of operating systems, java applications, XML, etc.

Difference Between ASCII and UNICODE

The following highlights all the important differences between ASCII and UNICODE −

Full form ASCII stands for American Standard Code for Information Interchange. UNICODE stands for Universal Character Set.
Mutual Relationship ASCII is a subset of UNICODE encoding scheme. UNICODE is a superset of ASCII.
Supporting Characters ASCII supports only 128 characters using 7-bit encoding scheme. It contains codes representing English characters, digits, and standard special symbols. UNICODE supports a wide range of characters. It supports 154 written scripts.
Bits Per Character ASCII uses 7-bit or 8-bits (Extended ASCII) to represent different characters. UNICODE uses mainly four character encoding schemes namely UTF-7 (7-bit), UTF-8 (8-bit), UTF-16 (16-bit), and UTF-32 (32-bit).
Memory Consumption ASCII consumes less memory. UNICODE consumes more memory as compared to ASCII.
Characters Represented ASCII can represent only English letters, digits, certain mathematical symbols, and some grammatical symbols, etc. UNICODE can represent a large range characters, special symbols, formulae, etc. from different languages such as English, Latin, Greek, etc.
First Edition Release The first edition of ASCII was released in 1963. The first edition of UNICODE was released in 1991.
Applications ASCII encoding scheme is used in computers and other electronic devices for exchange of data. It is also used in programming languages like HTML. UNICODE is used by IT industries for encoding and character representation in computers.


Both ASCII and UNICODE are the character encoding schemes used in electronic communication. From the above comparison of ASCII and UNICODE, we can state the most significant difference between them that is, ASCII is a basic encoding scheme that represents 128 characters in 7-bit encoding, whereas UNICODE is a vast ocean of text, numbers, mathematical symbols, emojis, formulae, etc. that can be mapped in different bit sizes. However, ASCII is a proper subset of UNICODE, hence UNICODE can represent all the characters in ASCII.