Unicode Filename Normalization Tool

Have you ever sent a file from a Mac to Windows and seen "résumé.pdf" turn into "re´sume´.pdf"? You can fix that problem with this tool!

View detailed explanation

This happens because Windows/Linux store Unicode filenames using NFC (composed form), while macOS stores them using NFD (decomposed form).

Upload a file to check whether its filename is normalized as NFC, NFD, NFKC, or NFKD. You can also download the file with your preferred normalization. Downloading in NFC ensures filenames created on Mac won’t break on Windows.

🔒 Don’t worry! Files are never uploaded to a server. All filename transformations happen locally in your browser. If you don’t believe it, open Developer Tools (F12) and verify it yourself!

Select files or drop them below
Drag & Drop files here
Or click to select (multiple files supported)
※ Downloading in NFC format prevents filename corruption on Windows.
#Original filenameDetected normalizationActions
No files yet.
Advanced view: Code points (selected row)
Click a row to display code points below.

⚠️ It has been confirmed that when uploading files in Chrome and Firefox on macOS, filenames are always sent in NFD form. As a result, even NFC files may be detected as NFD. This issue only affects normalization detection and does not impact the downloaded files. Safari does not appear to have this issue. If you would like to verify the normalization form on macOS, we recommend using Safari.

⚠️ Older Macs (before macOS High Sierra, 2017) using HFS/HFS+ always store filenames in NFD format. In such cases, please use a filesystem that supports NFC.

CLI Tool
I previously created a CLI tool called "unicode_norm" to solve this issue. If you can’t access this website, you can use that tool instead. Since installing CLI tools can be a barrier, I created this web version for convenience.

GitHub link
YouTube introduction video
Support Me
Support the developer. Your support greatly helps with updates and the development of new services.