⌘ K
utf-8 → hex · 4 formats · live

Convert Text to hex

Encode UTF-8 text to hexadecimal bytes. Choose space-separated, joined, 0x-prefixed, or \\x-prefixed output, in lower or upper case. All processing runs locally.

Text to Hex
Input
13 B
1 lines
Output
38 B
1 lines
Status
ready
live
Ratio
2.92×
out/in
input · text
output · hex
48 65 6c 6c 6f 2c 20 77 6f 72 6c 64 21
Quick Start

How to encode text as hex

UTF-8 bytes are emitted in lower or upper case hex pairs. Pick a separator/prefix to match the language or tool that will consume the output.

  1. 01

    Type or paste text

    Any UTF-8 input — emoji, accents, Unicode.

    Bytes flow through TextEncoder/TextDecoder for predictable UTF-8 semantics — emoji, surrogate pairs, and combining marks all encode losslessly.

    inputUTF-8TextEncoderlosslesslive
    input · raw bytestext · UTF-8
    Hello
    loaded · UTF-8MIME · ready
  2. 02

    Choose format

    Space-separated for readability, 0x/\\x for source code, joined for hashing.

    Hash and signature operations call crypto.subtle from the Web Crypto API, so output matches OpenSSL / Node bit-for-bit.

    fmtWeb Cryptosubtledeterministiclive
    fmt · options0x · live
    0x48 0x65
    options applied · livelive
  3. 03

    Toggle case

    Lower case by default; UPPER for protocols that prefer it.

    Options re-run instantly through useEffect + useMemo — switching URL-safe mode or padding doesn’t re-encode from scratch.

    casememoisedoptionsinstantreactive
    case · encodedlower · ready
    48 65 6c 6c 6f
    encoded · livelossless
  4. 04

    Copy or download

    One click to clipboard. Download as .txt.

    Copy uses the Async Clipboard API; downloads ship via Blob with the appropriate MIME (text/plain, image/png, …) so external tools recognise them.

    exportclipboardblobMIME-correctclient-side
    ok · copiedready · done
    Copied
    shipped · ready to shipsuccess
Pro tips

Encoding without surprises

Always UTF-8 first

Use TextEncoder / TextDecoder for bytes ↔ string conversion. btoa alone breaks on non-ASCII.

URL-safe vs standard Base64

Standard uses +, /, =; URL-safe swaps to -, _, no padding. Don’t mix them.

Hashes aren’t passwords

SHA-256 is fast; that’s good for fingerprints, bad for passwords. Use bcrypt / argon2 for credentials.

Watch padding rules

Some decoders are strict about = padding, others auto-pad. If round-trips fail at exactly 1 or 2 bytes, check padding.

Use Web Crypto for keys

Generate cryptographic keys via crypto.subtle, never Math.random. The latter is predictable.

JWT decode ≠ verify

Decoding a JWT just splits and base64-decodes. Verification needs the issuer’s public key / shared secret.

Related toolsHex to TextBase64 EncoderASCII ConverterUnicode ConverterURL EncoderText to Binary
Use Cases

When to encode hex

Protocols, source literals, debug output.

Binary literals

Drop into C/Rust/Go source as \x or 0x arrays. Output round-trips losslessly with the matching decoder — both run client-side, so end-to-end testing happens in a single tab. Encoding flows through TextEncoder for predictable UTF-8 semantics.

RFC-compliant

Test fixtures

Pin exact byte sequences in your test suite. Web Crypto's subtle.digest produces output that matches OpenSSL, GPG, and Node's crypto module byte-for-byte. That makes the result trustworthy as a content fingerprint, ETag, or integrity check.

OpenSSL-matched

Wire formats

Inspect what a serializer will produce on the wire. Pairs cleanly with HMAC, JWT, and signed-URL workflows where bit-level correctness matters. The browser's crypto stack is FIPS 140-validated in Chrome and Firefox, so it's production-grade.

lossless

Cryptography

Feed plaintext into hex-input hash/HMAC tools. Output uses canonical RFC 4648 / 7515 alphabets so curl, openssl, and any standards-compliant decoder accept it as input. URL-safe variants drop padding for tokens that travel in query strings.

byte-identical

Hexdump compare

Generate reference output to diff against hexdump. Heavy hashing runs through useMemo so large inputs don't block typing. PBKDF2, bcrypt, and Argon2 expose configurable cost factors — tune for your threat model, not the default.

spec-grade

URL-encoded equivalents

Cross-check %XX percent encoding with raw hex. Same input plus same options always yields identical bytes. That's the foundation for content-addressed storage (IPFS, Git, S3 ETags) and means the output is safe to commit to fixtures.

production-ready
FAQ

Frequently asked questions

Multi-byte characters expand to multiple bytes. 'é' becomes c3 a9 — two bytes in hex.
Some protocols (MAC addresses, SHA digests in certain tools) prefer upper case. The byte values are identical.
0x is the C/JavaScript number literal style. \x is the C/Python string escape style. Pick whichever your destination expects.
Encoded as UTF-8 bytes. The hex output will have more bytes than characters in the input.
No. Encoding runs locally in your browser.
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