ASCII to Hex Converter

A computer stores text as bytes, numbers from 0 to 255, and hex writes each byte with two digits, from 00 to FF. In ASCII, the basic code of English letters, digits and signs, H is 48, e is 65 and a space is 20, so Hello becomes 48 65 6C 6C 6F. Type or paste text into the first field and the hex codes appear as you type. Characters beyond ASCII, such as é, ß, Я or 字, take two to four bytes in UTF-8, the encoding of the web: é is C3 A9. Under “Encoding” you can also choose UTF-16, “Unicode code points” or an older code page such as Windows-1252, Windows-1251 or Shift_JIS; characters an encoding does not have are listed under the result.

Under “Separator” choose a space, nothing, a new line or a comma between the bytes, and under “Before each byte” add 0x, as in 0x48, or the backslash form used in program strings; “Lowercase letters” gives 6c instead of 6C. “Open a file” turns any file of up to 1 MB into its hex bytes, which is handy for looking inside a small file. “Swap” turns the hex back into text, so you can check the result, and everything runs in your browser: your text is not sent anywhere.