Unicode Normalizer (NFC, NFD, NFKC, NFKD)

NFC is the safest default for storage, transport, and the web — it's the shortest canonical form and what most systems expect. Use NFD when a system requires decomposed text (e.g. some macOS contexts). Use NFKC/NFKD only when you deliberately want compatibility folding (ligatures, full-width, super/subscripts collapsed), since those are lossy transformations.

It decomposes the text (NFD), removes all combining marks, then re-normalizes to your chosen form — so 'café' becomes 'cafe' and 'Crème Brûlée' becomes 'Creme Brulee'. This is handy for building ASCII slugs or accent-insensitive search keys, but it changes meaning in many languages, so don't use it on text you need to keep correct.

Decomposed forms (NFD/NFKD) often use more code points — a precomposed 'é' is one 2-byte character in UTF-8, while 'e' + combining acute is two characters totaling 3 bytes. Compatibility forms can go either way. The table lets you compare exact code-point and byte lengths.

NFC ↔ NFD is information-preserving and reversible for canonical equivalence. NFKC/NFKD are not reversible — once a ligature or full-width digit is folded, the original distinction is lost. Stripping diacritics is also one-way.