Check a byte sequence against the original ASCII character set. This mode accepts values from 0 through 127 and helps you inspect both readable characters and controls in a small sample of data.
| CHARACTER | H | e | l | l | o | space | w | o |
|---|---|---|---|---|---|---|---|---|
| BINARY | 01001000 | 01100101 | 01101100 | 01101100 | 01101111 | 00100000 | 01110111 | 01101111 |
| DECIMAL | 72 | 101 | 108 | 108 | 111 | 32 | 119 | 111 |
| HEX | 48 | 65 | 6C | 6C | 6F | 20 | 77 | 6F |
Each column is one byte. UTF-8 characters outside ASCII can span several columns.
ASCII is a seven-bit code. Here, values are displayed as eight-bit bytes with a leading zero, so uppercase A is 01000001, decimal 65, or hexadecimal 41. Use eight-bit groups separated by spaces when preparing binary input.
Try 01001000 01101001 to decode Hi. Then inspect 00001010, the line feed value. It affects the layout of text instead of displaying as a letter. The byte inspector names controls so that otherwise invisible data can be checked directly.
A byte can hold values up to 255, but standard ASCII stops at 127. A value such as 11111111 is therefore a valid byte and invalid ASCII. This tool rejects it instead of guessing a character from an unrelated character set.
This distinction matters when reviewing a protocol sample or a field that must remain ASCII. If you expect accented letters or emoji, return to binary-to-text mode and choose UTF-8, provided that is the source encoding. The label extended ASCII does not identify one universal mapping for bytes above 127.
A few useful details for this tool.
The leading zero makes the displayed value fit a full byte. It does not expand ASCII's range or change the value of the other seven bits.
No. ASCII includes controls and the delete value as well as printable characters. Check labels such as NUL, HT, LF, and CR in the inspector when a result looks empty or has unexpected spacing.
No. Emoji are outside ASCII. A UTF-8 emoji uses multiple bytes; those bytes must be decoded together using UTF-8 rather than treated as separate ASCII characters.