How to use the Hex Dump Viewer
- 1. Pick a sourceChoose a file from your device or type some text.
- 2. View the dumpSee offsets, 16 bytes per line in hex, and printable characters.
- 3. Check the file typeRead the detected type from the first bytes, and download the dump.
Reading a hex dump
Each line has three parts: the offset of its first byte in hexadecimal, 16 bytes as two-digit hex values (with a gap after eight), and the same bytes as ASCII, where unprintable bytes show as dots. It is the same layout as hexdump -C on Linux and macOS.
Worked example: "Hello, World!" is 13 bytes. Its line starts with offset 00000000, then 48 65 6c 6c 6f 2c 20 57, a gap, 6f 72 6c 64 21, and ends with |Hello, World!|. 48 is H, 65 is e and 20 is a space, so you can read text straight from the hex once you know a few values.
Magic bytes and practical uses
- File type detection: PNG files start 89 50 4E 47, PDFs start %PDF (25 50 44 46), ZIP-based files such as DOCX start PK (50 4B 03 04), and Windows executables start MZ.
- Security: an "invoice.pdf" that starts with MZ is really a program, a classic malware trick.
- Debugging: spot hidden byte-order marks (EF BB BF), Windows line endings (0D 0A) or stray null bytes.
- Learning: see how UTF-8 stores Hindi or emoji as several bytes.
The viewer shows the first 64 KB on screen and lets you download the complete dump as text, for files up to 50 MB. Everything is read locally in your browser. Hash the same file with the file hash checker, or try byte-level encryption with the XOR cipher tool.
Frequently asked questions
Why are some characters shown as dots?
Bytes outside printable ASCII (below 32, 127 and above) have no simple character, so they appear as dots in the right-hand column.
Can I edit the bytes?
No. This is a viewer. Use a hex editor app to change files.
Is the Hex Dump Viewer free?
Yes, the Hex Dump Viewer is free. The first time you view your first dump, you are asked for your name and WhatsApp number once. After that, this and every other Uncodemy tool opens straight away without the form.