Unicode Converter

A Unicode code point is a number assigned to a character: U+0041 is A, U+20B9 is the rupee sign, U+1F600 is a grinning face. An encoding is a separate question: it decides how that number becomes bytes. UTF-8 uses one byte for the ASCII range, two for most European and Middle Eastern scripts, three for most of Asia and four for emoji and historic scripts. So a string of ten characters can be ten bytes or forty depending entirely on what those characters are, which is why a database column sized in bytes and a form validated in characters disagree so reliably.

The count gets stranger with emoji. Many are not one code point but several joined by a zero-width joiner, U+200D. A family emoji can be built from four person emoji plus three joiners: seven code points, rendered as one glyph, and counted as anything from one to eleven depending on what is doing the counting. Skin tone modifiers work the same way, appending a separate code point to a base character. This is why deleting an emoji sometimes takes several backspaces and why truncating a string by byte length can split a character in half and produce a replacement glyph.

Two other categories are worth recognising when they appear in output. Combining characters modify the character before them, so an accented letter can exist either as a single precomposed code point or as a base letter plus a combining accent: visually identical, different data, and not equal in a string comparison unless both sides are normalised first. And the invisible characters (zero-width spaces, non-breaking spaces, directional marks) are the usual explanation for text that looks correct and refuses to match, sort or import. Converting to code points is the fastest way to see them, because nothing else makes them visible.