What does NFKD normalisation do?

NFKD stands for Normalization Form KD, or Compatibility Decomposition. It is the most aggressive form: it folds compatibility variants such as ligatures and full-width letters and also splits precomposed characters into a base plus combining marks, with no recomposition.

How is NFKD different from NFD?

NFD only performs canonical decomposition and keeps the original characters. NFKD additionally folds compatibility variants, so the ligature fi becomes f and i and the full-width A becomes a normal A, then everything is fully decomposed.

Why would I choose NFKD over NFKC?

NFKD leaves combining marks separate instead of recomposing them, which is convenient when you want to inspect or strip individual diacritics. NFKC gives the same folding but recombines marks into precomposed characters.

Yes, it can be. Compatibility folding discards styling like superscripts and ligature glyphs, and that cannot be undone. Use NFKD for matching, search, and analysis rather than to preserve formatted text.

Does my text leave the browser?

No. The tool uses the native String.prototype.normalize function, so NFKD decomposition runs entirely in your browser and nothing is uploaded.

Unicode NFKD Decomposer

NFKD (Normalization Form KD) is the most thorough Unicode normalisation: it folds compatibility variants like ligatures and full-width letters and then fully decomposes precomposed characters into base letters plus combining marks. The result exposes every individual element, which is ideal for analysis, matching, and accent stripping. This tool applies NFKD and lists the code points before and after.

How it works

NFKD is a compatibility decomposition with no recomposition step:

ﬁ  ->  f i
Ａ  ->  A
é   ->  e + ◌́   (U+0065 U+0301)
²   ->  2

Combining marks are placed in canonical order so equivalent inputs always produce the same output. Because compatibility variants are folded and precomposed characters are split, the code point count usually grows. The tool uses the engine’s native String.prototype.normalize("NFKD").

Notes and example

NFKD pairs well with accent stripping: after decomposition, drop everything in the combining diacritical marks block (U+0300 to U+036F) to turn café into cafe and ﬁancé into fiance. Like NFKC the folding is lossy, so use NFKD for comparison and search rather than for storing display text. For the same folding with marks recombined, use the NFKC normaliser.