Hex decoder.

Hexadecimal, Base16, writes every byte as two digits from 0 to 9 and A to F. Each digit is four bits, so the mapping is direct: no grouping, no padding, no arithmetic. It is the way bytes are shown in debuggers, hash digests, colour values and memory dumps.

A byte is split into two nibbles of four bits, each written as one of 16 digits: 0x48 is 01001000, the H of ASCII, written 48. The output is exactly twice the size of the input. Upper and lower case mean the same thing; the decoder reads both, with or without spaces or 0x prefixes.

Hash digests (a SHA-256 is 64 hex digits), CSS colours (#FF5733), MAC addresses, memory addresses, cryptographic keys and IVs, file signatures (a PNG starts 89 50 4E 47), and every hex dump a developer reads.

Yes: digits and letters only, nothing to escape.

Twice the size of the bytes, the worst of the practical encodings, and the most readable: a byte is two digits and you can see them. Use it to show bytes to a person; use Base64 to carry them.

No. Hex is an encoding, not encryption: it changes how bytes are written, not who can read them, and anyone can decode it with no key. Encrypt first (AES, age, a library's sealed box) when the content needs protecting, then encode the ciphertext if it has to travel as text.

Paste the Hex and the text appears as you type; the status line says how many characters became how many bytes. Spaces and line breaks are ignored, so a wrapped value from an email or a config file pastes as it is. Press Swap to encode the result again.

The decoder gives you the bytes as UTF-8 text when they are text. When they aren't, an image or a PDF for instance, it still shows them, with replacement characters where the bytes aren't valid UTF-8, and the status line says so. Use Hex to file to download the bytes as they are instead.

Hex uses 0 to 9 and A to F, and the error names the first character that isn't among them. Check for a stray quote, a trailing comma or a prefix from the surrounding code. Spaces, line breaks and 0x prefixes are dropped for you, and the count of digits has to be even.

Nothing leaves your browser. The text is read into memory on your machine and the encoding is computed there, in plain JavaScript; the page makes no request with it. Load the page, go offline and it keeps working.

No. The Hex decoder is free and opens without a sign-in, an account or an install.

Nothing. The Hex decoder holds your input in the page's memory, so closing or reloading the tab clears it, and it saves nothing in this browser.

It takes digits 0 to 9 and a to f in either case, two to a byte, ignoring spaces and 0x prefixes. Anything else stops with a message naming the first character it can't read.

Yes: drop a text file that holds the Hex on the input. The file is read as text and decoded, so a saved encoding doesn't need pasting.

Press Swap once there is a result and the same tool becomes the Hex encoder, with the decoded text moved into the input.

Closest to the Hex decoder: Hex encoder, Hex to file, File to Hex, Binary decoder. Each opens on its own page, free and in the browser.

The Hex decoder is one of 32 in its group. The group's page, /tools/encoding, lists them all.

The tool is free. Its interface is built from shadcn.io's own components (Button, Input, Slider and the rest of the registry under /ui), which come in React, Vue, Svelte and Solid. Pro adds the blocks and templates for the product around it.