File tools

Various tools for working with files and file formats.

Please note that these tools aren't optimized for large amounts of data, processing can slow down or run into problems once you reach above 150,000 characters. A cap of 1 million characters is currently in place.

Check file type

Select a file to check its file type / header. Only the first 16 bytes of each file are read and then discarded, no files are actually uploaded or stored anywhere. Files are matches against the File headers table below and won't catch everything. Feel free to reach out if there's a header missing or one you think would be worth adding.

A list of common file headers in hexadecimal format, useful if you have a chunk of data so you can quickly match it with a potential file type.

More information is available on the File signatures Wikipedia page.

Description Header Extensions
BMP file, a bitmap format used mostly in the Windows world 42 4D bmp, dib
Compound File Binary Format, a container format defined by Microsoft COM. It can contain the equivalent of files and directories. It is used by Windows Installer and for documents in older versions of Microsoft Office. It can be used by other programs as well that rely on the COM and OLE API's. D0 CF 11 E0 A1 B1 1A E1 doc, xls, ppt, msi, msg, vsd, wps, db
DOS MZ executable and its descendants (including NE and PE) 4D 5A exe, dll, mui, sys, scr, cpl, ocx, ax, iec, ime, rs, tsp, fon, efi
Image file encoded in the Graphics Interchange Format (GIF) 49 44 33 03 37 gif
49 44 33 03 39
GIF87a 47 49 46 38 37 61 gif
GIF89a 47 49 46 38 39 61 gif
JPEG raw or in the JFIF or Exif file format FF D8 FF DB jpg, jpeg
FF D8 FF E0 00 10 4A 46 49 46 00 01
FF D8 FF E0
FF D8 FF EE
FF D8 FF E1 ?? ?? 45 78 69 66 00 00
FF D8 FF E1
FF D8 FF E0
JPEG 2000 FF 4F FF 51 jp2, j2k, jpf, jpm, jpg2, j2c, jpc, jpx, mj2
00 00 00 0C 6A 50 20 20 0D 0A 87 0A
MIDI sound file 4D 54 68 64 midi
MPEG-1 Layer 3 file without an ID3 tag or with an ID3v1 tag (which is appended at the end of the file) FF FB mp3
FF F3
FF F2
MP3 file with an ID3v2 container 49 44 33 03 mp3
49 44 33 04
ISO Base Media file (MPEG-4) 66 74 79 70 69 73 6F 6D mp4
MPEG-4 video file 66 74 79 70 6D 70 34 32 mp4
66 74 79 70 4D 53 4E 56
MPEG-4 video file v2 00 00 00 18 66 74 79 70 6d 70 34 32 mp4
Ogg, an open source media container format 4F 67 67 53 ogg, oga, ogv
PDF document 25 50 44 46 pdf
Image encoded in the Portable Network Graphics format 89 50 4E 47 0D 0A 1A 0A png
89 50 4E 47 0D 0A 1A 0A 00 00 00 0D 49 48 44 52
Photoshop Document file, Adobe Photoshop's native file format 38 42 50 53 psd
Rich Text Format 7B 5C 72 74 66 31 rtf
OpenSSH private key file 2D 2D 2D 2D 2D 42 45 47 49 4E 20 4F 50 45 4E 53 53 48 20 50 52 49 56 41 54 45 20 4B 45 59 2D 2D 2D 2D 2D
OpenSSH public key file 2D 2D 2D 2D 2D 42 45 47 49 4E 20 53 53 48 32 20 4B 45 59 2D 2D 2D 2D 2D pub
UTF-8 byte order mark, commonly seen in text files EF BB BF txt, others
UTF-16LE byte order mark, commonly seen in text files FF FE txt, others
UTF-16BE byte order mark, commonly seen in text files FE FF txt, others
UTF-32LE byte order mark for text FF FE 00 00 txt, others
UTF-32BE byte order mark for text 00 00 FE FF txt, others
UTF-16BE byte order mark, commonly seen in text files EF BB BF txt, others
Waveform Audio File Format 52 49 46 46 wav
GZIP compressed file 1F 8B gz, tar.gz
7-Zip File Format 37 7A BC AF 27 1C 7z
XZ compression utility using LZMA2 compression FD 37 7A 58 5A 00 xz, tar.xz
Zip file format and formats based on it, such as EPUB, JAR, ODF, OOXML 50 4B 03 04 zip, aar, apk, docx, epub, ipa, jar, kmz, maff, msix, odp, ods, odt, pk3, pk4, pptx, usdz, vsdx, xlsx, xpi
50 4B 05 06
50 4B 07 08