Unicode Normalizer

About Unicode Normalizer

The same visible character can be encoded multiple ways in Unicode — an 'é' can be stored as a single precomposed code point (U+00E9) or as a base 'e' followed by a combining acute accent (U+0301). This matters more than it appears: two strings that look identical on screen may fail a strict equality check, break text search, or produce duplicate entries in a database because they use different normalization forms. Unicode Normalizer converts text between the four Unicode normalization forms defined by the Unicode Standard — NFC, NFD, NFKC, and NFKD — and shows a summary of how many characters changed. NFC is the preferred form for most storage and interchange; NFKC additionally maps compatibility characters like full-width letters and ligatures to their canonical equivalents.

Why use Unicode Normalizer

How to use Unicode Normalizer

1. Paste your text into the input area.
2. Select the target normalization form: NFC, NFD, NFKC, or NFKD.
3. The normalized output appears instantly with a change summary.
4. Compare the original and normalized character counts to understand the transformation.
5. Use the diff summary to see which characters were affected.
6. Click Copy to copy the normalized text to your clipboard.

When to use Unicode Normalizer

• When preparing user-input text for database storage to ensure consistent string comparison.
• When building a search index and needing all text variants to match the same normalized form.
• When comparing two strings that look identical but fail equality checks due to different normalization.
• When processing text from multiple sources (APIs, OCR, clipboard) that may use different normalization conventions.
• When cleaning up text containing full-width Unicode characters from East Asian keyboard input that should be standard ASCII.
• When preparing multilingual text for NLP pipelines that require a consistent Unicode representation.

Examples

Tips

• Always apply NFC normalization to user-submitted text before storing it in a database to prevent identical-looking duplicate records.
• Use NFKC when sanitizing text from East Asian input methods where full-width ASCII characters are common.
• The change summary helps you audit whether normalization accidentally modified text you did not intend to change.
• For text search, normalize both the query string and the indexed content to the same form (NFC or NFKC) so searches never miss matches due to form differences.
• Pair Unicode normalization with Hidden Character Detector to catch zero-width spaces and other invisible characters that normalization does not remove.

Frequently Asked Questions

Explore the category

Glossary

NFC (Canonical Decomposition + Composition)

Unicode normalization form that represents characters in precomposed form where possible. The recommended form for most text storage and interchange.

NFD (Canonical Decomposition)

Unicode normalization form that decomposes precomposed characters into their base characters and combining marks.

NFKC (Compatibility Decomposition + Composition)

Like NFC but also maps compatibility variants (full-width characters, ligatures, circled numbers) to their standard equivalents.

NFKD (Compatibility Decomposition)

Like NFD but also applies compatibility mappings. The most decomposed form, mapping all compatibility and precomposed characters to base forms.

Combining character

A Unicode character that modifies the preceding base character. The acute accent U+0301 is a combining character that turns 'e' into 'é' in NFD form.

Canonical equivalence

Two Unicode strings are canonically equivalent if they represent the same abstract character sequence, even if the underlying code point sequences differ due to normalization.