Hex Encoder / Decoder
Convert text to a hexadecimal string, or decode hex back to text — with byte delimiters, uppercase, and 0x / \x prefixes. Decoding ignores spacing and prefixes, so any format round-trips. Runs entirely in your browser, no server, no sign-up.
What this tool does
Convert any text to a hexadecimal string, or decode a hex string back to the original text — instantly, right in your browser. Nothing is sent to a server: it runs locally, works offline, and needs no sign-up. Pick a Mode, then optionally choose a byte delimiter, uppercase digits, or a per-byte prefix.
Modes
| Mode | What it does |
|---|---|
| encode (default) | Turns your text into hex — e.g. Hi becomes 4869 (each byte is two hex digits). |
| decode | Reverses it — turns a hex string back into the original text. Decoding is case-insensitive and ignores whitespace, delimiters, and 0x / \x prefixes. |
Formatting options (encode)
| Option | What it does | Example |
|---|---|---|
| Byte delimiter | Inserts a separator between bytes — none (default), space, colon, dash, comma, or newline. | Hi · colon → 48:69 |
| Uppercase hex | Emits uppercase A–F digits instead of lowercase. | é → C3A9 |
| Per-byte prefix | Adds 0x or \x before each byte. | Hi · 0x + space → 0x48 0x69 |
Mix and match freely — e.g. a space delimiter plus the 0x prefix gives the
classic 0x48 0x69 0x21 C-array style.
Decode output — text or raw bytes
| Format | When decoding |
|---|---|
| text (default) | Renders the bytes as UTF-8 text (errors if they aren't valid UTF-8) |
| bytes | Shows the decoded bytes as a plain lowercase hex byte string — use this for binary data that isn't readable text |
Examples
| Input | Settings | Output |
|---|---|---|
Hi | encode | 4869 |
Hello | encode · space delimiter | 48 65 6c 6c 6f |
Hello | encode · colon · uppercase | 48:65:6C:6C:6F |
Hi | encode · 0x prefix · space | 0x48 0x69 |
4869 | decode | Hi |
48:65:6c 6c 6f | decode | Hello |
c3a9 | decode | é |
FAQ
Is it free and private?
Yes — your input never leaves your device, and it keeps working offline once the page has loaded.
What encoding does it use for text?
Text is read and written as UTF-8, so
accented letters and emoji become their multi-byte UTF-8 sequences (é → c3a9).
Can I paste hex with spaces or colons?
Yes. Decoding ignores ASCII whitespace,
the : - , delimiters, and 0x / \x prefixes, so a string copied from a hex
dump, a 0x-prefixed C array, or a \x-escaped string all decode without editing.
My decoded output looks garbled.
The bytes probably aren't UTF-8 text. Switch the Decode output to bytes to see the raw hex instead.
Lowercase or uppercase?
Lowercase is the default and the most common in tools
and protocols. Toggle Uppercase hex when a spec or system expects A–F caps.
Developer & Automation Access
Run it from the terminal
Same engine as this page, headless — via the gizza CLI:
gizza tool hex-codec "Hello, world!"New to the CLI? Get gizza →
Open it by URL
Pre-fill and auto-run this tool with query parameters — the names match the API/CLI:
https://gizza.ai/tools/hex-codec/?input=Hello%2C%20world%21&mode=encode&format=text&delimiter=none&uppercase=true&prefix=noneMachine-readable descriptor: tool.json — title + parameters JSON Schema for agents.