How to use the online hex editor
- Drop a file onto the box or click it to choose one. Any type works: executables, images, archives, firmware or save games.
- Scroll or use the arrow keys to move through the bytes. Click a byte and type two hex digits to change it; changed bytes turn red and Undo (Ctrl+Z) reverts them.
- Search for hex bytes or text, jump to an offset, then click Download to save the edited file.
How to read a hex dump
Each row of the hex viewer shows 16 bytes. The left column is the offset of the first byte in hexadecimal, the middle shows every byte as two hex digits, and the right column shows the same bytes as ASCII characters; bytes that are not printable appear as dots.
00000010 48 65 6C 6C 6F 0A … Hello.
This row starts at offset 10 hex = byte 16 of the file, and 48 65 6C 6C 6F spells “Hello”.
File signatures (magic numbers)
Most file formats begin with a fixed byte sequence, so the first row of a hex dump tells you what a file really is, whatever its extension says.
| File type | First bytes | As text |
|---|---|---|
| PNG image | 89 50 4E 47 0D 0A 1A 0A | .PNG.... |
| JPEG image | FF D8 FF | ... |
| GIF image | 47 49 46 38 | GIF8 |
| PDF document | 25 50 44 46 | %PDF |
| ZIP, DOCX, XLSX, APK | 50 4B 03 04 | PK.. |
| Windows EXE or DLL | 4D 5A | MZ |
| Linux ELF program | 7F 45 4C 46 | .ELF |
| GZIP archive | 1F 8B | .. |
Number values and byte order
Select a byte to see the values that start there as unsigned and signed 8-, 16- and 32-bit integers. They are read in little-endian order, the lowest byte first, which is what x86 and ARM processors and most file formats use: the bytes 34 12 are the 16-bit number 0x1234 = 4660, and FF FF is 65535 unsigned or −1 signed.
Frequently asked questions
Is it safe to open private files?
Yes. The file is read with JavaScript inside your browser and never uploaded. You can even disconnect from the internet after the page has loaded.
How large can the file be?
Up to 1 GB, depending on your device's memory. Only the rows on screen are drawn, so scrolling stays fast even for files of hundreds of megabytes.
Can I insert or delete bytes?
No. The editor overwrites bytes in place, so the file size never changes. That is the safe mode for patching executables, firmware and save files, where shifting data would break every offset after it.
How do I search for text?
Switch the search to Text and type a word: it is searched as UTF-8 and letters match regardless of case. Use Hex bytes for exact byte patterns such as 4D 5A. Enter finds the next match, Shift+Enter the previous one.