Files
Check, compare, split, join and rename your files right in the browser — verify checksums, find duplicates and spot disguised file types, with nothing uploaded. Learn more
Duplicate File Finder
Find exact duplicate files by content, not filename
File Byte Comparator
Compare two files byte-for-byte
File Checksum Verifier
Verify a file against a published checksum
File Joiner
Rejoin split parts back into one file
File Metadata Viewer
See a file's basic details instantly
File Name Sanitizer
Make a filename safe for any OS
File Splitter
Break a big file into smaller numbered parts
File Type/Signature Identifier
Spot a file's real type from its bytes, not its name
Local File Batch Renamer
Rename many files at once with one rule, download as a zip.
Local File Renamer
Build a new filename interactively from a template, download the renamed file.
Sized File Generator
Generate a dummy file of an exact size, for testing uploads or storage limits.
Check, compare, split and rename files without uploading them
Most online file tools make you upload your file to someone else's server first. These don't: every file is read by your own browser, and nothing leaves your device. That makes them safe for contracts, photos, backups and anything else you'd rather keep private.
Downloaded something important? The File Checksum Verifier confirms it matches the SHA-256 hash the publisher gave, so you know it arrived intact and untampered. The File Type Identifier reads a file's first bytes to reveal what it really is, catching a "photo.jpg" that is actually a program. The File Metadata Viewer shows size, type and last-modified date at a glance.
Tidying up a folder of photos or downloads? The Duplicate File Finder groups files with identical contents even when their names differ, and the File Byte Comparator tells you exactly where two versions of a file start to differ. The Batch Renamer applies one rule to a whole set of names, such as numbering, prefixes or find-and-replace, and gives you a zip. The Local File Renamer builds a single name piece by piece, and the File Name Sanitizer removes characters that Windows, macOS or Linux won't accept.
When a file is too big to email or upload, the File Splitter cuts it into numbered parts and the File Joiner puts them back together, byte for byte. For developers and IT teams, the Sized File Generator creates a test file of an exact size, up to 2 GB, so you can check upload limits and storage quotas.
Questions and answers
- Should I use the Duplicate File Finder or the File Byte Comparator?
- Use the Duplicate File Finder when you have a whole batch of files and want to know which ones are identical. It groups them by content, whatever they're called. Use the File Byte Comparator for exactly two files when you want detail: whether they match, where the first difference is, and how much of them is the same.
- What's the difference between the File Checksum Verifier and the File Type Identifier?
- They answer different questions. The Checksum Verifier asks "is this exactly the file the publisher released?" by comparing its SHA hash with the published one, so even a one-byte change is caught. The File Type Identifier asks "what kind of file is this really?" by reading its first few bytes, which spots a file whose extension has been changed to disguise it. For a download you don't fully trust, run both.
- Will the File Joiner rebuild a file that was split by another program?
- Usually, yes, as long as that program simply cut the file into consecutive pieces, as the File Splitter here does. Select every part together and check the order shown before you join. Numbers in the names are read as numbers, so part 9 comes before part 10. Tools that compress or add headers to each part, such as multi-part RAR or 7-Zip archives, need their own software to rejoin.
- Batch Renamer or Local File Renamer: which do I need?
- The Batch Renamer applies one rule to many files at once, such as adding a prefix, numbering in sequence, changing case or finding and replacing text. It shows a live preview and gives you a zip. The Local File Renamer is for a single file whose new name you want to build by hand, with buttons to insert today's date, the original name or a counter.
- Do these tools change my original files?
- No. A web page can't edit or delete files on your computer, so your originals always stay exactly as they were. The renamers, splitter and joiner give you new copies to download, and the checking tools only read your files.