String to Hex Converter — Text to Hexadecimal Bytes Online
Convert any text (UTF-8) to its hexadecimal byte representation. Configurable separator (space / comma / none), lowercase / uppercase, and optional "0x" prefix per byte. Handles emoji, CJK, and every Unicode character correctly. 100% local.
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CommentsEnter text to get its UTF-8 hexadecimal byte representation. Each byte becomes 2 hex chars — 'A' → '41', '中' → 'e4 b8 ad', '😀' → 'f0 9f 98 80'. Pick separator (space / comma / hyphen / none / newline), case, and optional '0x' prefix.
What is String to Hex?
Text-to-hex is the two-step transformation: text → UTF-8 bytes → 2 hex chars per byte. Getting UTF-8 right matters — legacy 'ASCII to hex' tools produce nonsense for any character outside 0–127 (accents, CJK, emoji). This tool uses the browser's built-in TextEncoder for a fully Unicode-conformant UTF-8 encoding, then formats each byte as a 2-digit hex number. The output is byte-for-byte identical to what you'd get from Python's `text.encode('utf-8').hex()`, Node's `Buffer.from(text, 'utf8').toString('hex')`, and Go's `hex.EncodeToString([]byte(text))`.
How to convert text to hex online
- 1Paste text into the input pane.
- 2Pick a byte separator (single space is the most common; 'none' produces a continuous hex string).
- 3Choose lowercase (default, matches Python / Node convention) or uppercase.
- 4Optionally add '0x' prefix per byte — handy when copying into C-style array literals.
Use Cases
Inspect what a database is really storing
See exactly which bytes VARCHAR is going to store — critical when a column mixes emoji, CJK, and Latin-1 legacy data.
Build test fixtures for byte-level protocols
Generate exact hex payloads for network / device tests — copy directly into a Wireshark, netcat, or Postman raw body.
Debug encoding mismatches
When a string looks wrong on the wire, comparing the actual hex against the expected reveals whether it was double-encoded, wrong-encoded (Latin-1 vs UTF-8), or truncated.
Prepare data for hash / signature demos
Every crypto library operates on bytes. Getting a canonical hex representation lets you paste into openssl, sha256sum, or a REPL.
Key Concepts
- UTF-8
- The dominant Unicode encoding on the web. Variable-length: 1 byte for ASCII, 2 for most Latin extended, 3 for CJK, 4 for emoji and rare scripts.
- Hex byte
- 2 hexadecimal digits (00–FF) representing 8 bits of raw data — the standard human-readable format for binary content.
Tips & Best Practices
- ▸The 'none' separator with lowercase is the format Python's `.hex()` uses — great for comparing outputs across languages.
- ▸For debugging, put emoji at the start of your input — you'll immediately see 4-byte UTF-8 sequences and can visually confirm the tool works.
- ▸If you need Latin-1 (single-byte) encoding for legacy protocol interop, this tool can't do it; use a Python REPL. UTF-8 has been the correct default since 1993.
- ▸The reverse tool (Hex to String) accepts every separator format — round-tripping is free.
Frequently Asked Questions
How is text turned into hex?
The text is first encoded as UTF-8 (the modern default), then each byte becomes a 2-digit hex number. So 'A' (U+0041) → '41', 'é' (U+00E9) → 'c3 a9' (2 bytes), '😀' (U+1F600) → 'f0 9f 98 80' (4 bytes).
Is this the same as ASCII to hex?
For characters in the ASCII range (0–127), UTF-8 and ASCII produce identical hex. For anything beyond that — accents, CJK, emoji — UTF-8 uses 2–4 bytes per character. Pure ASCII-to-hex tools break on such input; this one doesn't.
Can I get output without any separator?
Yes — pick 'none' as the separator to get a continuous hex string like '48656c6c6f'. Or pick space, comma, hyphen, or newline.
Does uppercase / lowercase matter?
For decoding, no — the reverse tool accepts both. For readability and machine parsing, lowercase is the most common convention (matches Python's .hex() and Node's Buffer.toString('hex')).
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