ASCII to Binary Converter
Convert ASCII to Binary instantly in your browser.
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Everything is converted in your browser. Nothing you paste is uploaded or stored.
Worked example
Each row shows a short sample written as ASCII, and the same value converted to Binary.
| ASCII input | Binary output |
|---|---|
| 72 105 | 01001000 01101001 |
| 83 71 | 01010011 01000111 |
| 116 111 111 108 | 01110100 01101111 01101111 01101100 |
About these formats
ASCII represents each character as its numeric character code, written in decimal and separated by spaces. The original standard covers codes 0 to 127, which is why plain English text maps to values below 128.
Binary is base 2, the representation a computer actually works in. Each byte becomes eight digits of 0 and 1, so the capital letter A (value 65) is written 01000001.
How to use this converter
- Paste or type your ASCII into the left box.
- The Binary output appears immediately on the right — there is no button to press.
- Use Copy result to put the output on your clipboard, or Swap direction to convert Binary back to ASCII.
Values may be separated by spaces or commas. For fixed-width formats you can also paste one unbroken run of digits and it will be split correctly.
When you would use this
Converting ASCII to Binary comes up when you are debugging data that crosses a boundary — a file format, a network protocol, a database column, or a language runtime that reports values in a different base than your source.
It is also a common teaching exercise: seeing the same value in both ASCII and Binary makes the relationship between character encodings and number bases concrete in a way that reading about it does not.
Frequently asked questions
Is my data sent anywhere?
No. The conversion runs entirely in your browser using JavaScript. Nothing you paste leaves your device, is logged, or is stored.
How should I separate values?
Spaces work, and so do commas, colons and semicolons. For binary, hex and octal you can also paste a single unbroken run of digits — it is split into bytes automatically.
Does it handle emoji and non-English text?
Yes. Text is treated as UTF-8, so accented characters, Chinese, Tamil and emoji all convert correctly. They simply take more than one byte each.
Why did I get an error?
The input contained a character that is not valid for the source format, a value above 255, or a run of digits that does not divide evenly into bytes. The message names the specific token so you can find it.