Normalize Unicode

Free

Convert Unicode text to a standard form using NFC, NFD, NFKC, or NFKD normalization.

Input Text

Normalization Form

Normalized Text

Unicode Normalization Forms:

NFC (Canonical Composition): Most common form. Composes characters where possible. Recommended for most uses, web content, and storage.

NFD (Canonical Decomposition): Decomposes characters into base + combining marks. Useful for text processing and sorting.

NFKC (Compatibility Composition): Like NFC but also normalizes compatibility characters (e.g., ﬁ → fi, ① → 1). Good for search indexing.

NFKD (Compatibility Decomposition): Like NFD but also decomposes compatibility characters. Maximum decomposition for comparison.

Example: The character "é" can be represented as one character (U+00E9) or two (e + combining accent U+0301). Normalization makes these equivalent.

What is Unicode Normalization?

Unicode normalization is the process of converting Unicode text into a consistent, standardized form. The same visible character can often be represented in multiple ways in Unicode. For example, the letter "é" can be stored as a single character (U+00E9) or as "e" followed by a combining acute accent (U+0065 + U+0301). Normalization ensures these different representations are converted to a single canonical form.

Why Normalize Unicode?

Text Comparison: Ensure two visually identical strings compare as equal
Database Storage: Maintain consistency when storing text data
Search & Indexing: Make text searchable regardless of how it was input
Security: Prevent Unicode-based attacks and spoofing
Interoperability: Ensure text works across different systems and platforms

Normalization Forms Explained

NFC (Canonical Decomposition, followed by Canonical Composition)

The most commonly used form. Characters are decomposed and then recomposed into their precomposed form where available. This is the W3C recommended form for web content and the default for most applications.

NFD (Canonical Decomposition)

Characters are fully decomposed into their constituent parts. Base characters and combining marks are separated. Useful for text processing, sorting, and when you need to analyze or manipulate individual character components.

NFKC (Compatibility Decomposition, followed by Canonical Composition)

Like NFC, but also replaces compatibility characters with their canonical equivalents. Ligatures like "ﬁ" become "fi", and characters like "①" become "1". Ideal for search indexing and text matching.

NFKD (Compatibility Decomposition)

Maximum decomposition - both canonical and compatibility decomposition. All composed characters and compatibility variants are broken down. Best for thorough text comparison and analysis.

Common Use Cases

Web Development: Ensure consistent text handling across browsers
Data Processing: Clean and standardize text data before processing
Search Engines: Index text in a normalized form for better matching
File Systems: Handle filenames consistently across platforms
User Authentication: Normalize usernames to prevent spoofing
Internationalization: Ensure proper text handling for multiple languages

Which Form Should I Use?

NFC - Use for general text storage, web content, and most applications. This is the default recommendation.

NFD - Use when you need to process or analyze individual character components.

NFKC - Use for search indexing, username validation, or when you want to treat compatibility characters as equivalent.

NFKD - Use for maximum compatibility decomposition or thorough text analysis.