Binary to ASCII Converter
Paste 8-bit binary bytes and get plain ASCII characters back, with diagnostics when something is off.
Going the other way? Use the ASCII to binary converter.
To convert binary to ASCII, split the digits into 8-bit bytes, turn each byte into its decimal value, and look that value up in the ASCII table. The two bytes 01001000 01101001 are worth 72 and 105, and the table maps those to the letters H and i.
How it works
ASCII is the original character table: 128 characters, each with a fixed code number from 0 to 127. Binary text is just those code numbers written in base 2, one byte per character. So decoding is a three-step walk: split, convert, look up.
Worked example. Paste 01001000 01101001 into the converter. It splits the input into two bytes. The first, 01001000, converts to 72, and code 72 is capital H. The second, 01101001, converts to 105, which is lowercase i. Output: "Hi".
The strict part of this page is deliberate. Because ASCII stops at 127, any byte starting with a 1 is outside the table, and this converter tells you which byte broke rather than printing a replacement character and moving on. That makes it a good validity checker: if your bytes all decode cleanly here, they are plain ASCII, which also means they are valid UTF-8. If you see errors about bytes above 127, your data is probably UTF-8 text with accents or emoji, and the binary translator will decode it properly.
Delimiters are flexible on the input side. Spaces, commas, dashes, or no separator at all are fine; a continuous run of digits gets split into bytes from the left. The one thing that genuinely breaks decoding is a missing digit, which the diagnostics call out with the exact group that came up short.
ASCII table excerpt: A to J
| Character | Decimal | Binary |
|---|---|---|
| A | 65 | 01000001 |
| B | 66 | 01000010 |
| C | 67 | 01000011 |
| D | 68 | 01000100 |
| E | 69 | 01000101 |
| F | 70 | 01000110 |
| G | 71 | 01000111 |
| H | 72 | 01001000 |
| I | 73 | 01001001 |
| J | 74 | 01001010 |
Consecutive letters have consecutive codes, so the bytes count up one at a time. The full letter table lives on the binary alphabet page.
FAQ
How do I convert binary to ASCII?
Split the binary into groups of eight digits, convert each group to its decimal value, then look each value up in the ASCII table. The string 01001000 01101001 splits into two bytes worth 72 and 105, which the table maps to H and i, spelling "Hi".
What happens if a byte is above 127?
ASCII only defines codes 0 through 127, so a byte above that has no ASCII character. This converter flags the exact byte instead of printing a wrong guess. Bytes above 127 usually mean the data is UTF-8, so try the main binary translator, which decodes UTF-8 properly.
Why does my binary show a "7 bits" error?
Your digit count is not a multiple of eight, almost always because a leading zero got trimmed somewhere. ASCII codes for common letters start with 0, and dropping it breaks the byte grouping. The error names the short group so you can put the missing 0 back.