Binary Code Alphabet

In eight-bit ASCII display, uppercase A–Z runs from 01000001 to 01011010, with decimal values 65–90. Lowercase a–z runs from 01100001 to 01111010, with decimal values 97–122. Use the printable table to look up each letter. These are ASCII assignments, not the mapping used by five-bit A1Z26 or ITA2.

• Learn how to use the table
• Compare five-bit alphabets

The main table includes all 95 printable ASCII values, from space at 32 through tilde at 126. The control-character section lists selected non-printing values, not all of them. ASCII has 128 values in total; use the linked RFC for the complete set, including controls 0–31 and DEL at 127.

• View selected non-printing values
• Open the ASCII reference source

ASCII needs seven bits for values 0–127. This reference pads each value with a leading zero to show it in an eight-bit byte: A is 1000001 in seven bits and 01000001 in the table. The extra zero changes display width, not the character set, and does not make this an extended ASCII table.

• Compare ASCII storage and Unicode

ASCII assigns separate values to uppercase and lowercase letters. A is decimal 65, binary 01000001; a is decimal 97, binary 01100001. Each ASCII letter pair differs by 32. Preserve the byte values when copying a message, because changing case changes the data rather than just the way a letter is drawn.

• Compare case and digit values

The character 1 has ASCII value 49, written as the byte 00110001. The binary integer 1 is the number one, which is a different interpretation. Similarly, the text 10 contains two character bytes, while the binary number 10 equals decimal 2. Choose a text or number converter according to what the source represents.

• Convert unsigned numbers
• Encode text digits

Space is the printable value 32, shown as 00100000. Tab, line feed, and carriage return are non-printing controls: 00001001, 00001010, and 00001101 respectively. They appear in the control-character section instead of the printable grid. A result containing these bytes may look blank or move the cursor without showing a letter.

• Look up selected control codes

Those characters are outside ASCII's 0–127 range and are not missing rows in this table. Use the UTF-8 text encoder to inspect their complete byte sequences. There is no single universal extended ASCII table for all non-English text. For example, UTF-8 é uses 11000011 10101001, which must be decoded together.

• Inspect multilingual UTF-8 examples

Use a row's copy button to copy its eight-bit value, or select the byte to open it in the homepage translator. The printable table contains each value 32–126 once. Use your browser's Print command for a paper reference; the print layout removes the copy controls. Keep seven-bit versus eight-bit display in mind when comparing another chart.

• Read the table instructions