Hex Viewer / Editor

This online hex viewer opens a file in your browser and shows it as its raw bytes; nothing is uploaded. Each byte is written as two hexadecimal digits from 00 to FF, so a file of any type — image, archive, executable, unknown blob — can be read the same way. It adds a text pane beside the hex, an offset column on the left, a detail panel for the selected byte, and a hex editor for changing bytes in place.

To look inside a file, drop it on the viewer: it works as a simple hex reader for any format, up to 100 MB, and highlights known file-start markers so you can see what the file really is. If you only have a hex string rather than a file, paste it into the viewer and it becomes bytes you can scroll, search and inspect like a file.

Converting hex is a different job from viewing bytes. To turn a hex value into decimal, binary or another base, or to read it as text or as a big integer, use the Number Base Converter. To peel off Base64, hex, URL and other encoding layers, use the Encoding Auto-Decoder. Both can hand the bytes back here when you want to see where they sit in the file.

Each row starts with the offset of its first byte, followed by the bytes in hex and the same bytes as characters. Bytes between 0x20 and 0x7E show as printable ASCII; anything else shows as a dot, so readable text stands out on the right.

Byte order matters when a number spans several bytes. PNG stores lengths and sizes big-endian (most significant byte first), while formats such as BMP and WAV use little-endian, so the same value can look reversed between formats.

Typical jobs are repairing a damaged header so a file opens (for example restoring the first bytes of a JPEG to FF D8 FF), changing a single field such as an image dimension, finding data appended after a format's end marker (FF D9 for JPEG, the IEND chunk for PNG), and reading a message stored in a plain-text region.

After editing a PNG field you usually also need to fix its CRC; the PNG Chunk Analyzer can check and repair it. To find out what a file really is before you edit, run it through the File Type Detector.

As a hex editor it keeps edits in memory and shows them as changed bytes; your original file is never modified. Export writes a modified copy or a hex dump. Edits overwrite bytes in place, so you cannot insert or delete bytes and the file length stays the same.

A header field is rarely a single byte. A length, an offset or a timestamp is usually two, four or eight bytes read together, and the answer depends on byte order. Select a byte and the Data inspector reads up to eight bytes from that offset as 8, 16, 32 and 64-bit integers (signed and unsigned), Float32, Float64, an ASCII character and a UTF-8 character, in little-endian or big-endian order. For example the four bytes 78 56 34 12 are 305,419,896 read little-endian and 2,018,915,346 read big-endian.

The inspector reads the bytes as they currently are, so an edit shows up immediately, and a value that needs more bytes than remain in the file says so instead of guessing. Floating-point values are printed in the shortest form that reads back to the same number, so the bytes CD CC CC 3D read as little-endian Float32 show as 0.1. To convert a number between bases, or to read it as text, use the Number Base Converter.