UTF-8 Converter

UTF-8 is the way almost all text is stored on computers and sent over the web. Every character is saved as one to four bytes, and a UTF-8 converter shows you those bytes.

1. Type or paste your text into the box. The bytes appear straight away.
2. Pick how the bytes are written: hex (C3 A9) is the most common, decimal (195 169) is what many programming languages print, binary shows the bits, URL % is for links, and \x escapes is for code.
3. Open Bytes for each character to see which bytes belong to which letter.
4. Copy the result. To go the other way, click Bytes → text; the bytes are carried across and decoded.

It depends on the character. Plain English letters, digits and punctuation take one byte each, exactly as in ASCII. Accented letters need two, most other scripts and symbols need three, and emoji need four.

The first bits of each byte say what it is: a byte starting with 0 is a whole character, one starting with 110, 1110 or 11110 starts a 2-, 3- or 4-byte character, and one starting with 10 continues it. That is why a character count and a byte count can be very different: naïve is 5 characters but 6 bytes, and a single emoji is 4 bytes.

Unicode is the list: it gives every character a number, called a code point (é is U+00E9). UTF-8 is one way of storing those numbers as bytes (é becomes C3 A9). ASCII is the old 128-character set of English letters, digits and symbols.

UTF-8 was designed so that ASCII text is already valid UTF-8, byte for byte. That is a big reason it won: about 99% of websites use it today. Other Unicode encodings exist, mainly UTF-16, which Windows and Java use internally and which stores most characters in two bytes, but files and web pages are nearly always UTF-8.

If you need to squeeze text down to plain ASCII, for an old system that rejects accents, use the UTF-8 to ASCII converter.

A file shows strange characters when it was saved in one encoding and opened as another. Older Windows programs often save text and CSV files as Windows-1252 (also called ANSI), which breaks accents and symbols in anything that expects UTF-8.

1. Click Open file and pick the text, CSV, subtitle or other plain-text file.
2. The tool reads it as UTF-8 if it can. If not, it reads it as Windows-1252 and tells you so. UTF-16 files are spotted by their first two bytes.
3. Check the text in the box looks right, then click Save as UTF-8. You get a copy named yourfile-utf8.csv.

Turn on Add BOM for Excel for CSV files you will open in Excel. The BOM is three bytes (EF BB BF) at the very start that tell Excel the file is UTF-8; without them, Excel may show Café instead of Café. Leave it off for web pages, code and data feeds, which don't need it.