A hex dump is a textual view of a file's raw bytes. Each line typically shows the byte offset, the bytes as two-digit hexadecimal, and an ASCII sidebar so you can spot text, headers and structure inside binary data.

Which bytes show as readable characters?

Printable ASCII bytes in the range 0x20 to 0x7e are shown as their character and highlighted. Every other byte, including control characters and high bytes, is shown as a dot in the ASCII column.

Is there a file size limit?

To stay responsive in the browser the viewer caps files at 16 MB and pages the output 4 KB at a time. For larger files, slice them first or use a desktop hex editor.

Is my file uploaded to a server?

No. The file is read locally using the browser FileReader API, so its contents never leave your device. That makes it safe for inspecting sensitive or proprietary files.

What is the offset column for?

The offset is the position of the first byte on that row, in hexadecimal. It lets you reference a specific byte by address, which is essential when following a file-format spec or a struct layout.

Hex Dump Viewer — Gera Tools

A hex dump is the classic way to look at the raw bytes of any file. It lines up three columns — the byte offset, the bytes as hexadecimal, and an ASCII sidebar — so you can find file signatures, embedded text, headers and padding inside otherwise opaque binary data. This viewer renders that layout in your browser for any file you drop in, with no upload.

How it works

The tool reads your file into a byte array using the browser’s FileReader API, then formats it row by row. For each row it prints:

The offset of the first byte on the line, in hexadecimal, padded to a consistent width.
The bytes themselves as two-digit hex values, with a small gap in the middle of the row for readability.
An ASCII sidebar where any printable byte (0x20–0x7e) appears as its character and everything else appears as a dot.

You can choose 8, 16, 24 or 32 bytes per row. Large files are paged 4 KB at a time so the page stays fast even on big inputs, and the offset column always reflects the true position within the whole file.

Tips

Hex dumps are most useful when you know what to look for. A PNG begins with 89 50 4e 47 (.PNG in ASCII), a PDF with 25 50 44 46 (%PDF), and a ZIP with 50 4b 03 04 (PK..). Scan the ASCII sidebar to spot human-readable strings such as metadata, URLs or error messages buried in a binary. Because the offset is shown in hex, you can cross-reference a byte position directly against a file-format specification or a C struct layout. Everything runs locally, so even sensitive files stay on your machine.